Issued  September  24,  1210. 

U.  S.  DEPARTMENT  OF  AGRICULTURE. 


FARMERS’  BULLETIN  408. 


SCHOOL  EXERCISES  IN  PLANT 

PRODUCTION. 


BY 


DICK  J.  CROSBY, 

Specialist  in  Agricultural  Education, 
Office  of  Experiment  Stations. 


WASHINGTON: 


GOVERNMENT  PRINTING  OFFICE 

1910. 


LETTER  OF  TRANSMITTAL. 


U.  S.  Department  of  Agriculture, 

Office  of  Experiment  Stations, 

Washington ,  D.  C.,  April  30,  1910. 

Sir:  Three  years  ago  the  Department  issued  as  Bulletin  No.  186, 
Office  of  Experiment  Stations,  a  publication  entitled  “  Exercises  in 
Elementary  Agriculture — Plant  Production.”  The  demand  for  this 
bulletin  has  been  large  and  continuous,  and  notwithstanding  the  fact 
that  four  editions  aggregating  22,000  copies  have  been  issued  the 
supply  is  now  exhausted.  The  bulletin  was  prepared  primarily  for 
the  use  of  public-school  teachers,  and  since  popular  interest  in  the 
teaching  of  agriculture  in  the  schools  is  growing  rapidly,  it  now 
seems  wise  to  reissue  the  exercises  in  the  Farmers’  Bulletin  series. 
With  this  aim  in  view  I  have  had  Parts  1  and  2  of  Bulletin  186,  deal¬ 
ing  with  the  plant  and  its  environment,  revised  for  publication  as  a 
Farmers’  Bulletin  on  “School  Exercises  in  Plant  Production.”  Part 
3,  of  Bulletin  186,  “Lessons  on  Corn,”  will  be  revised  and  combined 
with  Circular  96  of  this  Office,  “How  to  Test  Seed  Corn  in  Schools,” 
for  publication  as  a  Farmers’  Bulletin  on  “School  Lessons  on  Corn.” 
Respectfully, 

A.  C.  True, 

Director 

Hon.  James  Wilson, 

Secretary  of  Agriculture . 

408 

2 


CONTENTS. 


Pasre 

Purpose  of  the  bulletin .  7 

Scope  of  the  bulletin .  S 

Materials  for  laboratory  exercises .  8 

General  plan  of  laboratory  exercises .  10 

Exercises  in  plant  production .  12 

Part  1. — The  plant .  12 

Exercise  1. — To  show  that  plants  absorb  moisture  from  the  soil .  12 

Exercise  2. — How  roots  absorb  moisture .  13 

Exercise  3. — To  show  that  plants  get  food  from  the  soil .  15 

Exercise  4. — To  show  that  plants  give  off  moisture .  16 

Exercise  5. — To  show  the  rise  of  water  in  plants .  16 

Exercise  6. — Circulation  of  water  in  plants .  16 

Exercise  7. — To  show  that  part  of  the  moisture  absorbed  by  the  roots 

of  plants  is  retained  in  the  plant .  17 

Exercise  8. — To  show  that  plants  get  food  from  the  air .  17 

Exercise  9. — How  plants  grow. . . .  18 

Propagation .  19 

Exercise  10. — Spores .  19 

Exercise  11. — Seeds — germination  test .  20 

Exercise  12. — To  make  a  balance .  21 

Exercise  13. — Seeds — purity  test .  23 

Exercise  14. — Development  of  young  plants  from  seeds .  25 

Exercise  15. — To  show  that  young  plants  get  food  from  seeds .  26 

Exercise  16. — Pollination .  26 

Exercise  17. — Layering .  27 

Facilities  for  rooting  cuttings . ' .  29 

Exercise  18. — To  make  soft  cuttings .  30 

Exercise  19. — To  make  hard  cuttings .  30 

Exercise  20. — To  make  grafting  wax .  31 

Exercise  21. — Cleft  grafting . -  -  -  32 

Exercise  22. — Whip  grafting .  33 

Exercise  23. — Budding .  34 

Part  2. — The  environment  of  the  plant .  36 

Exercise  24. — Conditions  essential  to  plant  growth — light . 36 

Exercise  25. — Conditions  essential  to  plant  growth — heat .  36 

Exercise  26. — Conditions  essential  to  plant  growth — moisture .  37 

Exercise  27. — Conditions  essential  to  plant  growth — air .  37 

Exercise  28. — Soil  collection . 

Exercise  29: — Classification  of  soils . - . 

Exercise  30. — Light  and  heavy  soils . 

Exercise  31. — Porosity — the  capacity  of  soils  to  take  in  rainfall . 

Exercise  32. — Air  in  soils .  ^ 

408 


3 


4 


CONTENTS. 


Exercises  in  plant  production — Continued. 

Part  2. — The  environment  of  the  plant — Continued.  Page. 

Exercise  33. — Capillarity — the  power  of  soils  to  take  up  moisture  from 

below .  40 

Exercise  34. — Puddling .  41 

Exercise  35. — The  effect  of  lime  on  clay  soils .  41 

Exercise  36. — Action  of  frost  on  soils .  42 

Exercise  37. — Temperature  of  soils  as  affected  by  color .  42 

Exercise  38. — Temperature  as  affected  by  moisture .  43 

Exercise  39. — Temperature  of  soils  as  affected  by  inclination  of  the 

surface  or  exposure  to  the  sun .  43 

Exercise  40. — Free  moisture  in  soils . . .  43 

Exercise  41. — Capillary  moisture  in  soils .  44 

Exercise  42. — Hygroscopic  moisture  in  soils .  44 

Exercise  43. — The  influence  of  tillage  and  mulches  on  the  retention  of 

moisture  in  soils .  45 

Exercise  44. — To  show  the  effect  of  plowing  down  manures  and  clods  .  45 

Exercise  45. — Influence  of  drainage  upon  plant  growth .  45 

Exercise  46. — Effect  of  manures  on  plant  growth .  46 

Helps  for  teachers .  47 

408 


ILLUSTRATIONS. 


Page. 

Fig.  1.  An  alcohol  lamp  made  from  a  tin  box .  9 

2.  Wash  bottle .  10 

3.  A  homemade  garden  line .  10 

4.  A  stamen .  11 

5.  A  pistil .  11 

6.  Vertical  section  of  a  tomato  blossom .  11 

7.  To  show  that  plants  absorb  moisture  from  the  soil .  13 

8.  To  show  osmosis .  14 

9.  Osmosis  shown  with  bladder  membrane .  14 

10.  To  show  that  plants  give  off  a  part  of  the  moisture  absorbed  from  the 

soil .  16 

11.  To  show  where  roots  increase  in  length .  18 

12.  Seed-testing  device .  20 

13.  A  simple  balance .  21 

14.  A  serviceable  tripod  magnifying  glass  and  a  convenient  mount  for  pre¬ 

serving  seeds  for  study .  24 

15.  Device  showing  proper  depth  to  plant  seeds .  25 

16.  To  show  the  best  depths  at  which  to  plant  corn .  26 

17.  Plant  food  in  seeds .  26 

18.  Tomato  blossom  ready  to  pollinate .  27 

19.  Tip  layering .  28 

20.  Vine  layering .  28 

21.  Mound  layering .  29 

22.  Frame  for  rooting  cuttings .  29 

23.  Leaf  cutting — part  of  leaf .  30 

24.  Leaf  cutting — whole  leaf .  30 

25.  Stem  cutting  or  “slip ”  of  Coleus .  31 

26.  Cutting  set  in  trench .  31 

27.  Cuttings:  a,  Simple  cutting;  5,  heel  cutting;  c,  mallet  cutting;  d, 

single-eye  cutting .  31 

28.  Grafting  tool .  32 

29.  Cleft  grafting:  a,  Scion;  b ,  scions  inserted  in  cleft .  32 

30.  Cross  section  of  stock  and  scion .  33 

31.  Whip  grafting:  a,  The  stock;  b,  the  scion;  c,  stock  and  scion  united.. .  33 

32.  A  bud  stick .  34 

33.  Cutting  the  bud .  34 

34.  Budding:  Preparing  the  stock . 

35.  Budding:  a,  Inserting  the  bud;  b,  tying;  c,  cutting  off  the  top . 

36.  Method  of  demonstrating  the  effect  of  too  much  water  in  soil . 

37.  Arrangement  for  showing  the  effect  of  the  exclusion  of  air  on  plant 

growth . 

38.  Apparatus  to  test  the  capacity  of  soils  to  take  in  rainfall . 

39.  Apparatus  to  test  the  power  of  soils  to  take  up  moisture  from  below... 

408 

5 


Digitized  by  the  Internet  Archive 
in  2018  with  funding  from 
University  of  North  Carolina  at  Chapel  Hill 


https://archive.org/details/schoolexercisesi4014cros 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


PURPOSE  OF  THE  BULLETIN. 

This  bulletin  supersedes  a  similar  bulletin  of  the  Office  of  Experi¬ 
ment  Stations.®  It  is  intended  as  a  laboratory  guide  or  manual  for 
the  use  of  teachers  and  not  as  a  text-book  to  be  studied  by  the 
pupils.  It  is  expected  that  the  pupils  will  use  a  text-book  on  agri¬ 
culture  and  that  teachers  will  provide  themselves  with  text-books 
and  other  helps  as  suggested  in  the  section  on  “  Helps  for  Teachers.” 
They  should  also  prepare  themselves  in  advance  on  each  lesson  by 
working  out  the  necessary  exercises  and  familiarizing  themselves 
with  all  details  of  the  work.  In  this  wav  they  will  learn  what  diffi- 
culties  are  likely  to  arise  and  what  details  of  the  less  complicated 
exercises  can  safely  be  intrusted  to  the  older  pupils  in  the  class  in 
agriculture,  thus  saving  time  for  themselves  and  increasing  the  value 
of  the  exercises  to  the  pupils. 

While  success  in  this  work  will  depend  largely  upon  the  personal 
influence  and  work  of  the  teacher,  there  is  nevertheless  a  duty  incum¬ 
bent  upon  school  officers  to  improve  the  physical  and  material 
equipment  of  the  schools.  The  very  lowest  requirements  that  could 
be  considered  adequate  for  carrying  through  these  exercises  are 
warm,  light,  well-ventilated  schoolrooms — warm  enough  to  protect 
tender  growing  plants  from  cold  at  all  times. 

While  many  of  the  exercises  could  be  performed  in  any  sort  of 
room,  or  even  out  of  doors,  the  series  can  not  be  followed  out  in  the 
order  given  unless  provision  is  made  for  growing  plants  in  the  school¬ 
room.  And  it  is  a  matter  of  some  importance  that  the  exercises  be 
taken  up  in  the  order  given,  so  that  each  step  may  lead  naturally 
and  logically  to  the  next.  In  the  earlier  nature-study  work  of  the 
grades,  formality,  order,  and  the  other  accompaniments  of  science 
are  kept  in  the  background,  so  as  to  reduce  to  the  lowest  terms  the 
embarrassment  of  getting  acquainted  with  the  “common  natural 
objects  and  processes  which  appeal  to  human  interest  directly.” 
But  now  that  the  pupils  are  to  take  up  the  more  formal  study  of 
elementary  agriculture,  they  should  proceed  in  a  more  orderly  way 

a  XJ.  S.  Department  of  Agriculture,  Office  of  Experiment  Stations  Bui.  186,  Exci- 
cises  in  Elementary  Agriculture. — Plant  Production.  This  bulletin  is  no  longer 
available  for  distribution  from  this  Department,  but  can  be  procured  for  10  cents 
from  the  Superintendent  of  Documents,  Washington,  D.  C. 

408 


7 


8 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


and  be  led  to  feel  that  in  nature  things  do  not  “just  happen/’  but 
follow  inexorable  laws  of  cause  and  effect.  It  is  for  the  purpose  of 
illustrating  the  application  of  some  of  these  laws  that  these  exercises 
have  been  brought  together. 

SCOPE  OF  THE  BULLETIN. 

The  course  in  agriculture  for  the  rural  common  schools,  as  outlined 
by  the  committee  on  instruction  in  agriculture  in  its  ninth  report  to 
the  Association  of  American  Agricultural  Colleges  and  Experiment 
Stations,®  was  designed  to  extend  over  two  years,  the  seventh  and 
eighth  years  in  schools  having  eight  grades.  The  first  year  was  to 
be  given  up  to  a  study  of  plant  production,  and  the  second  year  to 
animal  production  and  some  matters  concerning  dairying,  farm 
mechanics,  and  farm  accounts.  The  experiments  thus  far  tried  in 
teaching  agriculture  in  the  elementary  schools  have  been  directed 
mainly  along  the  line  of  plant  production;  hence  there  is  much  more 
material  in  teachable  form  on  this  phase  of  agriculture  than  on  any 
other  phase.  On  this  account,  and  for  the  further  reason  that  a  bul¬ 
letin  dealing  with  the  whole  subject  of  elementary  agriculture  would 
be  so  large  as  to  preclude  its  wide  distribution,  it  has  been  decided  to 
limit  this  bulletin  to  exercises  illustrating  some  of  the  more  important 
principles  of  plant  production,  leaving  to  subsequent  bulletins  the 
application  of  these  principles  to  particular  crops. 

MATERIALS  FOR  LABORATORY  EXERCISES. 

The  rural  elementary  school  is  fortunately  located  in  the  midst  of  a 
bountiful  supply  of  illustrative  material  for  the  outdoor  study  of  agri¬ 
cultural  subjects.  There  are  birds,  trees,  flowers,  growing  crops,  and 
other  nature-study  material  all  around  it;  land  for  school  and  home 
gardens  is  readily  available,  and  well-managed  farms  with  field  crops, 
live  stock,  farm  machinery,  and  good  buildings  are  usually  near  at 
hand.  Such  material  as  this  should  be  utilized  to  the  fullest  extent. 
Every  farm  and  home  in  the  district  should  contribute  to  the  agri¬ 
cultural  work  of  the  school,  and  the  farmers  themselves  should  be 
asked  to  talk  to  the  pupils  and  give  them  the  benefit  of  their  experi¬ 
ences.  In  this  way  “ training  in  the  elements  of  failure  and  success” 
can  be  effectively  given  and  the  patrons  of  the  school  can  be  made  to 
realize  that  the  elements  which  contribute  to  intellectual  training  and 
culture  are  not  all  confined  within  the  covers  of  text-books. 

But  while  it  will  be  best  to  take  the  pupils  out  of  doors  for  much  of 
their  practice  work,  some  of  the  principles  of  agriculture  do  not  lend 

a  United  States  Department  of  Agriculture,  Office  of  Experiment  Stations  Circ.  60, 
The  Teaching  of  Agriculture  in  the  Rural  Common  Schools,  and  Bui.  164,  Proceedings 
of  the  Nineteenth  Annual  Convention  of  the  Association  of  American  Agricultural 
Colleges  and  Experiment  Stations,  1905 
408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


9 

themselves  readily  to  illustration  in  this  manner.  There  is  need  of 
some  laboratory  work  which  can  best  be  performed  indoors  with  spe¬ 
cially  prepared  apparatus.  The  material  for  this  apparatus  is  inex¬ 
pensive,  and  much  of  it  could  be  provided  by  the  pupils.  Two  dozen 
empty  tomato  cans,  three  or  four  lard  pails,  a  few  baking-powder 
cans  and  covers,  a  lot  of  empty  bottles  and  corks  of  different  sizes,  a 
few  small  wooden  boxes,  some  empty  packing  boxes,  a  collection  of 
typical  soils  (clay,  sand,  loam,  and  muck  or  peat),  and  a  few  seeds  of 
garden  and  farm  crops,  will  enable  the  teacher  and  pupils  without 
expense  to  perform  a  variety  of  experiments  illustrating  important 
principles  upon  which  the  science  and  practice  of  agriculture  are 
based. 

If  to  this  material  the  school  board  or  the  pupils  will  add  by  pur¬ 
chase  an  8-ounce  glass  graduate  (10  cents),  a  simple  magnifying  glass 
(50  cents),  a  set  of  metric  weights  ($1),  4  dairy  thermometers  (SI), 
6  student-lamp  chimneys  (90  cents),  12  5-inch  test  tubes  (25  cents), 


Fig.  1. — An  alcohol  lamp  made  from  a  tin  box. 


a  yard  of  thin  muslin  or  cheese  cloth  (5  cents),  a  pint  glass  funnel 
(10  cents),  a  putty  knife  (15  to  25  cents),  a  grafting  tool  (50  to  75 
cents),  an  alcohol  lamp  (25  cents),  a  kitchen  scale  with  dial  which 
will  weigh  from  1  ounce  to  24  pounds  (90  cents),  12  ordinary  glass 
tumblers  (30  to  50  cents),  a  yard  of  bicycle  tire  tape  or  surgeon’s 
adhesive  plaster,  a  }^ard  of  quarter-inch  glass  tubing,  3  large  iron 
spoons,  and  a  few  ordinary  plates,  pie  tins,  etc.,  the  school  will  be 
provided  with  an  excellent  equipment  for  the  laboratory  exercises 
included  in  this  bulletin,  and  all  at  a  cost  of  $6  or  $7. 

It  will  not  be  necessary  to  purchase  all  of  the  articles  to  which 
prices  are  attached  in  this  list.  In  place  of  the  putty  knife,  which 
would  be  used  mainly  as  a  spatula  for  mixing  soils,  a  common,  thin 
case  knife  or  kitchen  knife  may  be  used.  A  heavy  pocketknife  ma j0 
be  used  in  place  of  the  grafting  tool. 

The  boys  can  easily  make  a  fairly  good  alcohol  lamp,  as  shown  in 
figure  1,  by  punching  a  hole  in  the  top  of  a  tin  box  and  inserting  a 
piece  of  soft  twine  for  a  wick. 

52472°— Bull.  408—10 - 2 


10 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


The  wash  bottle  shown  in  figure  2  is  a  very  convenient  piece  of 
apparatus,  and  is  easily  made  from  an  empty  bottle,  a  rubber  cork 
with  two  holes  through  it,  and  two  pieces  of  glass  tubing.  Hold  the 
tubing  in  the  alcohol  flame,  turning  it  slowly  to  heat  all  sides  alike, 

until  a  short  section  of  it  becomes  red- 
hot,  when  it  can  be  bent  as  shown  in  the 
illustration.  An  ordinary  cork  will  do 
nearly  as  well  as  a  rubber  cork,  and 
holes  can  be  burned  through  it  with  a 
red-hot  wire.  The  glass  tubing  should 
fit  tightly  in  the  cork.  To  operate  the 
bottle,  fill  it  two-thirds  full  of  water  and 
blow  on  it  at  A.  Water  will  be  forced 
out  at  B  in  a  small  stream,  which  can 
be  directed  against  the  inner  surfaces  of 
tumblers,  test  tubes,  tin  cans,  etc.,  to 
wash  down  soil  or  sediment  not  easily 
reached  in  any  other  way. 

The  pupils  should  be  encouraged  to 
make  and  set  up  as  much  as  possible  of 
the  apparatus.  They  should  be  taught 
how  to  melt  off  the  tops  of  tomato  cans 
neatly,  how  to  make  flats  °  and  other 
boxes  out  of  packing  boxes,  how  to 
make  soil  sieves  by  the  use  of  wire 
screens  on  bottomless  boxes,  to  make  garden  lines  (fig.  3),  stakes, 
and  numerous  other  things  that  will  be  needed  from  time  to  time  in 
these  exercises.  If  one  or  two  glass-covered 
frames  like  the  one  shown  in  figure  22  can  be 
made  soon  after  the  opening  of  the  fall  term, 
the  plants  needed  for  indoor  experiments 
can  be  grown  much  more  easily  and  they  can 
be  protected  better  from  cold.  By  mount¬ 
ing  such  frames  on  legs  instead  of  brackets 
they  can  be  moved  from  one  window  to  an¬ 
other  or  at  night  can  be  moved  away  from 
the  window  to  a  warmer  place.  This  work 
may  be  done  at  school  if  tools  are  available, 
otherwise  at  the  homes  of  the  pupils. 


Fig.  2. — Wash  bottle. 


Fig.  3. — A  homemade  garden  line. 


GENERAL  PLAN  OF  LABORATORY  EXER¬ 
CISES. 

«  No  claim  is  made  for  the  originality  of  these  exercises.  The 
attempt  has  been  rather  to  arrange  the  work  in  a  progressive  and 
connected  way,  so  that  when  completed  it  will  give  the  pupils  a 

a  A  flat  is  a  box  about  2  feet  wide,  3  feet  long,  and  3  inches  deep,  and  is  used  for 
starting  cuttiDgs,  seeds,  etc. 

408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


11 


Anther- - 


a 


Strgma - C 


Style, - 


FiJament- 


Fig.  4.— A  stamen. 


Fig.  5. — A  pistil. 


fairly  connected  though  necessarily  imperfect  view  of  the  simpler 
phenomena  of  plant  production.  The  order  in  which  the  different 
exercises  are  presented  has  been  determined  partly  by  the  limits  of 
the  school  year  in  the  country  and  partly  by  the  outline  adopted  by 

the  committee  on  instruction  in 
agriculture  in  its  ninth  report. 

The  exercises  are  intended  to  ex¬ 
tend  over  one  school  year — the 
seventh  in  an  eight-grade  school. 

The  work  will  probably  be  taken 
up  in  the  fall  term,  hence  the  de¬ 
sirability  of  beginning  with  plant 
work  while  plants  are  still  grow¬ 
ing  out  of  doors.  In  winter 
when  outdoor  work  with  plants  Ovary-  f. — 
must  be  suspended  in  the  great 
majority  of  rural  schools,  the 
pupils  can  take  up  the  soil  ex¬ 
ercises,  grafting,  seed  testing, 

corn  judging,  etc.,  and  be  ready  when  spring  opens  for  the  study  of 
corn  and  other  field  crops. 

It  is  assumed  that  the  pupils  who  are  to  take  up  elementary  agri¬ 
culture  have  had  some  nature-study  work  and  in  this  way  have 
learned  something  of  the  structure  of  common  plants;  that  they 
know  the  names  and  un¬ 
derstand  to  some  extent  the 
functions  of  the  essential 
parts  of  common  plants — 
roots,  stems,  leaves,  and 
flowers,  including  the  re¬ 
productive  organs,  stamens, 
and  pistils  (figs.  4,  5,  and  6). 

If  the  pupils  do  not  have 
such  knowledge,  they  should 
spend  some  time  studying 
common  plants  like  portu- 
lacas,  morning  glories,  to¬ 
matoes,  corn,  squashes,  and 
pumpkins,  all  of  which  can 
usually  be  found  in  blossom 
and  in  fruit  at  the  opening 
of  the  fall  term  of  school, 
book  on  botany. 

Having  acquired  a  working  knowledge  of  plant  structure,  in  fact, 
while  they  are  acquiring  this  knowledge,  the  pupils  will  begin  to  ask 

408 


— Stigma, 


— Stamens 


rCorolia 


Fig.  6. — Vertical  section  of  a  tomato  blossom.  After  Burkett 
et  al.  Agriculture  for  Beginners. 

The  teacher  should  consult  some  text- 


12 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


what  plants  do — how  they  feed,  grow,  reproduce,  etc.,  and  this  is 
where  the  exercises  in  this  bulletin  begin.  The  study  of  plants  does 
not  proceed  very  far  before  their  dependence  upon  proper  conditions 
of  light,  heat,  moisture,  air,  soil,  and  other  physical  agencies  becomes 
apparent;  hence  the  reason  for  part  2  of  this  study — “The  Environ¬ 
ment  of  Plants.” 

Soils  and  climate  therefore  are  not  studied  because  of  their 
fundamental  importance,  but  because  of  their  influence  upon  plant 
production. 

EXERCISES  IN  PLANT  PRODUCTION.® 

PART  1.— THE  PLANT. 

Exercise  1. — To  Show  That  Plants  Absorb  Moisture  from  the  Soil. 

Take  two  1-quart  tin  cans  as  near  alike  as  you  can  get  them  and 
punch  holes  in  the  bottoms  for  drainage.  Secure  enough  garden  soil 
to  fill  both  cans,  mix  it  thoroughly,  and  sift  it  to  remove  pebbles  and 
clods.  Fill  both  cans  level  full  of  loose  soil,  which  should  then  be 
packed  by  jarring  each  can  three  times  on  the  table  or  floor.  It  is 
important  to  have  the  soil  packed  alike  in  both  cans.  Weigh  the 
filled  cans,  and  if  one  is  heavier  than  the  other,  take  out  enough  soil 
to  bring  them  to  the  same  weight. 

Plant  5  or  6  kernels  of  corn  in  one  can,  water  both  cans  alike,  and 
set  them  aside  for  the  corn  to  grow.  Whenever  water  is  applied  to 
the  can  containing  corn,  an  equal  amount  should  be  applied  to  the 
other  can  in  order  to  keep  both  soils  in  about  the  same  physical 
condition. 

When  the  corn  is  3  or  4  inches  high,  wet  both  soils  thoroughly, 
allow  the  cans  to  stand  until  water  ceases  to  drip  from  the  bottom, 
weigh  them,  and  record  their  weights  separately.  Set  both  cans  in 
a  warm  light  place  where  the  corn  will  continue  to  grow  rapidly. 
Weigh  the  cans  twice  on  the  following  day — morning  and  after¬ 
noon — and  record  the  weights.  Keep  this  up  for  three  or  four  days, 
or  until  the  corn  begins  to  suffer  from  lack  of  moisture.  Water 
again  and  continue  as  before.  You  will  probably  find  that  the  can 
containing  the  growing  plants  loses  moisture  much  more  rapidly 
than  the  other.  Why?  Compute  the  difference.  As  the  corn 
increases  in  size  does  it  use  more  or  less  water?  How  is  the  corn 
affected  when  the  soil  becomes  too  dry  ?  What  does  it  mean  when 
corn  in  the  field  “rolls”  or  “curls?” 

a  Notwithstanding  the  apparent  simplicity  of  the  exercises,  there  are  many  chances 
for  failure  unless  the  utmost  care  is  taken  to  follow  directions  and  to  eliminate  as  far  * 
as  possible  all  factors  except  those  needed  in  the  demonstration.  The  teacher  ought 
to  work  out  each  exercise  before  attempting  to  present  it  to  the  pupils. 

408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


13 


This  experiment  may  be  performed  in  another  way  by  using  flower 
pots  instead  of  tin  cans.  When  the  corn  is  3  or  4  inches  high,  get  two 
lard  pails  or  cans  just  large  enough  to  take  in  the  pots  to  their  rims, 
as  shown  in  figure  7.  Mark  on  the  outside  of  the  pails  the  depth  to 
which  the  pots  will  extend  on  the  inside,  and  at  a  point  1  inch  above 
each  mark  make  a  dent  which  can  be  distinctly  seen  on  the  inside  of 
the  pail.  Now  fill  each  pail  with  water  up  to  the  dent,  water  both  pots 
thoroughly,  and  set  them  in  the  pails  as  shown  in  the  figure.  Set 
both  pails  and  pots  in  a  warm,  light  place  so  that  the  corn  will  con¬ 
tinue  to  grow.  The  next  day  remove  the  pots,  and  you  will  probably 
find  that  the  water  is  not 
up  to  the  dents.  What  has 
become  of  it  ?  From  a  pre¬ 
vious  experiment  you  will 
probably  conclude  that  the 
soil  has  taken  it  up.  From 
an  8-ounce  graduate  pour 
into  one  pail  just  enough 
water  to  bring  it  up  to  the 
dent  again.  Make  a  record 
of  the  amount  necessary  to 
do  this.  Fill  the  graduate 
and  bring  the  water  in  the 
other  pail  up  to  the  dent. 

Again  record  the  amount  of 
water  used.  Repeat  these  operations  daily  for  two  or  three  weeks. 
Find  the  total  amount  of  water  added  to  each  pail. 

How  do  the  plants  take  up  the  water  ?  The  next  exercise  will  show. 


Fig.  7. — To  show  that  plants  absorb  moisture  from  the  soil. 


Note. — After  starting  exercise  1  prepare  also  exercise  3.  Both  exercises  will 
require  three  or  four  weeks  to*show  good  results.  While  waiting  for  the  plants  to 
grow  sufficiently  to  demonstrate  that  they  get  food  and  moisture  from  the  soil  the 
teacher  should  germinate  some  seeds  as  in  exercise  11,  so  that  when  reference  is  made 
to  root  hairs  in  exercise  2  there  will  be  root  hairs  to  show  the  pupils.  Do  not  at  this 
time  take  up  the  other  questions  involved  in  exercise  11.  Exercises  4  to  9,  inclusive, 
may  be  taken  up  before  the  completion  of  exercises  1  and  3,  if  there  is  time  for  them. 


Exercise  2. — How  Roots  Absorb  Moisture. 

(A)a  Materials. — Procure  a  wide-moutlied  bottle,  an  egg,  a  glass 
tube  3  or  4  inches  long  and  about  a  quarter  of  an  inch  in  diameter,  a 
candle,  and  a  piece  of  wire  about  5  inches  long. 

Experiment. — Remove  a  part  of  the  shell  from  the  large  end  of  the 
egg  without  breaking  the  skin  beneath.  This  is  easily  done  by  gently 

a  After  Goodrich.  Nature  Lessons  for  School  and  Farm.  Hampton  Normal  and 
Agricultural  Institute. 

408 


14 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


an 

pi 

1 

L 

tapping  the  shell  until  it  is  full  of  small  cracks  and  then  picking  off 
the  small  pieces.  In  this  way  take  the  shell  from  a  space  about  one- 
half  inch  in  diameter.  Remove  the  shell  from  the  small  end  over  a 
space  as  large  as  the  diameter  of  the  glass  tube.  Next  cut  from  the 
lower  end  of  the  candle  a  piece  about  one-half  inch  long;  bore  a  hole 
in  this  just  the  size  of  the  glass  tube.  Now  soften  one  end  of  this 

piece  of  candle  and  then  stick  it  onto  the 
small  end  of  the  egg  so  that  the  hole  in  the 
candle  comes  over  the  hole  in  the  shell.  Heat 
the  wire  and  with  it  solder  the  piece  of  candle 
more  firmly  to  the  egg,  making  a  water-tight 
joint.  Place  the  glass  tube  in  the  hole  in  the 
piece  of  candle  and  with  the  hot  wire  solder 
it  firmly.  Now  run  the  wire  down  the  tube 
and  break  the  skin  of  the  egg  just  under  the 
end  of  the  tube.  Then  fill  the  bottle  with 
water  until  it  overflows  and  set  the  egg  on 
the  bottle,  as  in  figure  8.  In  an  hour  or  so 
the  white  of  the 
egg  will  be  seen 
rising  in  the 
glass  tube,  be¬ 
cause  the  water 
is  making  its 
way  by  osmosis 
into  the  egg 
through  the 
skin,  which  has  no  opening  so  far  as  can 
be  found  with  the  most  powerful  micro¬ 
scope.  In  this  way  water  laden  with 
plant  food  enters  the  slender  root  hairs 
of  plants. 

This  process  of  osmosis  may  also  be 
shown  as  follows:  Remove  the  shell 
from  the  large  end  of  an  egg  without 
breaking  the  skin,  break  a  hole  in  the 
small  end  of  the  egg  and  empty  the 
shell,  rinse  it  out  with  water,  fill  the 
bottle  with  colored  water,  fill  the  egg 
partly  full  of  clear  water,  and  set  it  on  the  bottle  of  colored  water. 
Colored  water  will  gradually  pass  up  into  the  egg  and  color  the  water 
that  is  there.  Or  the  colored  water  may  be  put  into  the  eggshell 
at  the  start  and  the  clear  water  in  the  bottle.  In  that  case  coloring 
matter  will  pass  from  the  shell  to  the  bottle. 


Fig.  8. — To  show  osmosis. 


Fig.  9. — Osmosis  shown  with  bladder 
membrane. 


408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


15 


(B) a  The  method  by  which  plants  absorb  moisture  through  their 
roots  can  be  shown  in  another  way  by  the  use  of  the  apparatus  in 
figure  9.  Tie  a  piece  of  moistened  bladder  over  the  large  end  of  the 
thistle  tube  A,  as  shown  at  B,  previously  filling  the  tube  partly  full 
of  molasses.  Insert  the  tube  in  the  cork  of  a  wide-mouthed  bottle 
and  immerse  it  in  clear  water,  as  shown  in  the  accompanying  illus¬ 
tration.  In  the  course  of  a  few  hours  water  will  pass  through  the 
bladder  and  force  the  molasses  out  of  the  top  of  the  tube. 

Of  what  importance  is  it  to  know  that  the  roots  of  plants  take  up 
moisture  from  the  soil?  Does  this  have  anything  to  do  with  the 
feeding  of  plants  ? 

Exercise  3.— To  Show  that  Plants  Get  Food  from  the  Soil. 

Secure  about  2  quarts  of  clean  sand  and  heat  it  in  a  shovel  or  iron 
pan  until  all  vegetable  matter  is  burned  out.  Fill  two  large  tin 
tomato  cans,  or  other  similar  vessels,  having  holes  in  the  bottom  for 
drainage,  with  this  soil  and  plant  in  each  5  large,  plump  beans  as 
near  alike  as  possible,  which  have  been  soaked  overnight.  Water 
both  cans  with  rain  water  and  set  them  in  a  warm  place  for  the  beans 
to  grow. 

After  this  treat  both  cans  alike,  except  that  one  is  to  be  watered 
with  rain  water  and  the  other  with  soil  solution.6  After  the  beans 
are  up  pull  out  all  but  3  of  the  strongest  plants  in  each  can.  Con¬ 
tinue  watering  one  can  with  rain  water  and  the  other  with  soil  solu¬ 
tion  for  four  or  five  weeks.  By  that  time  the  beans  in  the  latter 
should  be  much  larger  and  stronger  than  the  others.  To  what  is 
this  difference  due  ?  Surely  not  to  differences  in  temperature  or  light 
or  soil  or  the  rain  water.  It  must  be  mainly  due,  then,  to  something 
dissolved  from  the  rich  soil  and  carried  in  solution  to  the  roots  of 
the  beans,  which  in  turn  pumped  it  up  to  the  stem  and  leaves  of  the 
beans. 

Plant  food  in  the  soil  is  dissolved  by  water  and  by  weak  acids 
given  off  by  the  root  hairs  much  in  the  same  way  that  sugar  and  salt 
are  dissolved.  In  this  condition  plant  food  can  be  taken  in  by  the 
roots  as  easily  as  pure  water,  and  water  may  be  rich  in  plant  food 
and  yet  remain  as  clear  as  pure  water.  We  think  of  the  “clear-as- 
crystal”  well  water  that  we  drink  as  being  pure  water,  but  we  know 
that  often  it  contains  so  much  lime  that  every  few  weeks  we  have  to 
chip  off  the  scale  of  lime  on  the  inside  of  the  teakettle. 

a  After  Burkett,  Stevens,  and  Hill.  Agriculture  for  Beginners. 

b  To  make  the  soil  solution,  fill  a  lard  pail  two-thirds  full  of  rich  garden  soil  or,  better, 
rich  soil  from  beneath  a  manure  heap,  and  add  enough  rain  water  to  make  a  thin  slop. 
Stir  this  thoroughly  and  set  it  aside  until  water  is  needed  for  the  beans,  then  strain  off 
some  of  the  water,  using  a  piece  of  thin  muslin  or  cheese  cloth  for  a  strainer.  A  new 
solution  should  be  made  up  about  once  a  week. 

408 


16 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


Well  water  may  also  contain  other  substances  in  solution.  Sup¬ 
pose  you  try  an  experiment  to  show  this  by  fastening  sprouted  kernels 
of  wheat  on  thin  slices  of  floating  cork  in  such  manner  that  the  roots 
will  hang  over  the  edges  of  the  cork  down  into  the  water.  Put 
some  of  the  seedlings  thus  arranged  into  a  tumbler  of  clean  rain 
water  and  others  into  a  tumbler  of  clean  well  water  and  watch  their 
development. 

Exercise  4. — To  Show  that  Plants  Give  off  Moisture. 

Take  a  plant  that  is  well  started  in  a  tomato  can  or  flower  pot,  a 
piece  of  cardboard,  and  a  glass  tumbler  or  jar  large  enough  to  cover 
the  plant.  Cut  a  slit  in  the  cardboard  and  draw  it  around  the  plant 

as  shown  in  figure  10.  Seal  the  slit  with 
pitch,  wax,  or  tallow  so  that  no  moist¬ 
ure  can  come  up  through  it  from  be¬ 
low;  cover  the  plant  with  the  glass  and 
set  it  in  a  warm,  sunny  place.  Moist¬ 
ure  will  condense  on  the  inner  surface 
of  the  glass.®  Where  does  it  come 
from  ?  Is  all  the  moisture  absorbed  by 
the  roots  given  off  in  this  way  ?  How 
can  you  find  out  ?  Why  do  plants 
need  water  ? 

Exercise  5. — To  Show  the  Rise  of  Water 

in  Plants. 

That  the  water  absorbed  by  the  roots 
of  plants  is  forced  upward  through  the 
plants  can  be  demonstrated  by  sever- 
fig.  io.— to  show  that  plants  give  off  ing  the  stem  of  a  geranium  3  or  4 

part  of  the  moisture  absorbed  from  the  incheg  from  the  surface  0f  the  Soil,  Set¬ 
ting  on  top  of  the  cut  end  of  the  stem 
a  section  of  glass  tubing  several  inches  long,  and  fastening  the  two 
together  by  wrapping  the  joint  with  a  strip  of  adhesive  tape  or  sur¬ 
geon’s  plaster.  Keep  the  root  of  the  plant  normal  by  supplying  it 
with  water.  Note  what  happens  inside  the  glass  tube,  making  obser¬ 
vations  every  few  hours. 

Exercise  6. — Circulation  of  Water  in  Plants. 

To  show  that  water  and  whatever  substances  it  holds  in  solution 
circulate  to  all  parts  of  the  plant,  fill  a  tumbler  about  one-third  full 
of  lukewarm  water  colored  with  a  few  drops  of  red  ink  or  some 

a  If  moisture  does  not  condense  readily  inside  the  glass,  cool  the  glass  by  exposing 
it  to  a  current  of  cold  air  or  by  wrapping  it  for  a  minute  or  two  in  a  cloth  wrung  out 
of  cold  water.  The  outside  of  the  glass  should  then  be  dried  so  that  the  moisture  on 
the  outside  will  not  obscure  that  within. 


408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


17 

other  brilliant  coloring  matter,  and  place  in  the  colored  water  the 
freshly  cut  stems  of  white  carnations,  white  roses,  lilies  of  the  valley, 
or  other  white  flowers,  or  the  twigs  of  trees  with  young  leaves  on, 
or  almost  any  soft  green  plant.  Be  sure  that  they  are  fresh.  In  a 
short  time  the  colored  water  will  rise  through  the  stems  or  twigs 
and  may  be  seen  distributed  in  vein-like  patterns  through  the  petals 
of  the  flowers  or  through  the  leaves.  Hold  the  leaves  up  to  the  light 
and  the  coloring  matter  can  be  seen  more  clearly.  In  this  manner 
the  stem  of  the  plant  carries  food  m  solution  which  has  been  absorbed 
by  the  roots. 

Exercise  7.  To  Show  that  Part  of  the  Moisture  Absorbed  by  the  Roots  of 

Plants  is  Retained  in  the  Plant. 

Pull  up  any  good-sized  green  plant  like  a  bunch  of  clover  or  a  pig 
weed,  weigh  it  carefully,  and  record  the  weight.  Now  put  it  in  a 
pie  tin,  tomato  can,  or  other  metal  receptacle,  and  set  in  the  bright 
sunlight  until  it  is  thoroughly  dry  and  brittle.  Weigh  again  and  by 
comparison  with  the  first  weight  determine  what  percentage  of  the 
plant  was  water. a  Using  this  result  as  a  basis  for  calculation,  how 
many  pounds  of  green  clover  will  it  take  to  make  a  ton  of  clover  hay? 

Put  the  dried  plant  in  an  oven  or  on  top  of  a  stove  over  a  slow  fire 
which  will  not  char  the  plant  and  see  if  any  more  moisture  can  be 
driven  off.* * 6  What  are  the  percentages  of  dry  material  and  water  as 
finally  determined  ?  We  have  found  that  part  of  the  water  taken  up 
by  the  roots  is  given  off  by  the  leaves  and  part  of  it  is  retained — 
enough  to  make  up  a  large  percentage  of  the  weight  of  herbaceous 
plants.  It  has  been  found  that  corn  roots  take  up  over  300  pounds 
of  water  for  every  pound  of  dry  matter  produced,  while  oats  and 
clover  take  up  over  500  pounds  of  water  for  every  pound  of  dry 
matter.  The  plant  food  is  therefore  taken  in  very  dilute  form. 

Exercise  8. — To  Show  that  Plants  Get  Food,  from  the  Air. 

Take  two  or  three  small  pieces  of  green  wood  a  half  inch  or  less 
in  diameter  (short  sections  of  a  small  twig  will  answer),  put  them 
into  a  test  tube  or  a  covered  pressed-tin  box  with  small  holes  in 
the  top  to  allow  the  escape  of  smoke  and  gas,  and  hold  over  a  hot 
fire  until  all  gas  and  smoke  have  been  driven  off.  Do  not  allow 
them  to  blaze.  What  remains  ?  What  color  is  it  ?  Apply  a  match 
to  one  of  the  pieces.  Does  it  burn  with  a  flame?  Will  it  burn  at 

a  If  the  school  scales  do  not  weigh  small  amounts  accurately, it  wTould  be  well  to  use 

more  green  material. 

&  A  safer  plan  than  that  above  would  be  to  heat  the  dried  plant  for  several  days  in  a 
double  boiler,  such  as  is  used  in  the  kitchen  for  cooking  oatmeal.  Such  a  boiler  can 
be  rigged  up  in  the  schoolroom  by  hanging  a  small  pail  containing  the  dried  plant 
inside  a  larger  pail  partly  filled  with  water. 

52472°— Bull.  408—10 - 3 


18 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


all?  It  answers  to  the  description  of  charcoal,  which  is  almost  pure 
carbon.  Boil  the  carbon  in  water  and  in  weak  acid  (vinegar)  to 
see  if  it  can  be  dissolved  in  either  of  these  liquids.  Do  you  think 
that  the  roots  of  plants  could  take  up  much  of  this  material  ? 

Put  a  tablespoonful  of  sifted  soil  (from  a  pot  in  which  a  plant  has 
been  growing)  in  an  iron  spoon  and  heat  it  red  hot.  Was  there  much 
material  to  burn  in  the  soil,  much  carbon  ?  Not  enough  will  be  found 
to  supply  plants  with  all  they  need  of  this  material,  which  constitutes 
nearly  one-half  of  their  solid  material.  It  must  come  mainly  from 
some  other  source. 

Now  put  the  charred  sticks  into  an  iron  spoon  and  heat  them  until 
only  ash  remains.  What  has  become  of  the  carbon?  It  has  com¬ 
bined  with  an  invisible  gas,  oxygen,  to  form  another  invisible  gas, 
carbon  dioxid,  or  carbonic-acid  gas,  which  mixes  with  the  air  and 
from  which  the  plant  may  take  it  in  through  the  leaves.  The  leaves 

discard  most  of  the  oxygen,  but 
the  carbon  is  sent  to  all  parts 
of  the  plant  and  built  into  the 
new  structure  representing  the 
season’s  growth. 

Exercise  9. — How  Plants  Grow.® 

To  show  where  roots  increase 
in  length,  place  some  kernels  of 
corn  or  other  large  seeds  be¬ 
tween  the  folds  of  a  piece  of 
wet  cloth.  Keep  the  cloth  wet 
till  the  seeds  have  sprouted  and 
the  young  plants  have  roots 
2  or  3  inches  long.  Have  at  hand  two  panes  of  glass  about  5  by  8 
inches,  a  piece  of  cloth  a  little  longer  than  the  width  of  the  glass  and 
about  3  inches  wide,  a  spool  of  dark-colored  thread,  and  a  shallow  pan 
or  dish.  Lay  one  pane  of  glass  in  the  pan,  letting  one  end  rest  on 
the  bottom  and  the  other  on  the  opposite  edge  of  the  pan  (fig.  11). 
Wet  the  cloth  and  spread  it  on  the  glass.  Take  one  of  the  sprouted 
seeds,  lay  it  on  the  cloth,  tie  pieces  of  thread  around  the  roots  at 
intervals  of  one-fourth  inch  (tie  carefully  so  that  the  roots  will  not 
be  injured),  or,  if  waterproof  ink  is  available,  mark  the  roots  with  a 
fine  pen  at  intervals  of  one-fourtli  inch;  place  the  second  pane  of  glass 
over  the  roots,  slipping  in  a  sliver  of  wood  to  prevent  crushing  them, 
and  letting  the  upper  edge  of  this  glass  come  just  below  the  seed. 
I  old  the  corners  of  the  cloth  about  the  seed,  put  half  an  inch  of  water 

Q  After  Goodrich.  Nature  Lessons  for  School  and  Farm.  Hampton  Normal  and 
Agricultural  Institute. 

408 


Fig.  11.— To  show  where  roots  increase  in  length. 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION.  19 

into  the  pan,  and  leave  for  development.  A  day  or  two  will  show 
conclusively  where  the  lengthening  takes  place.  Has  this  fact  any 
bearing  on  the  relation  of  soil  texture  to  root  development?  The 
soft,  tender  root  tips  will  force  their  way  through  a  mellow  soil  with 
greater  ease  and  rapidity  than  through  a  hard  soil,  and  the  more 
rapid  the  root  growth  the  more  rapid  the  development  of  the  plant. 
Here  is  the  lesson  of  deep  plowing  and  thorough  breaking  and  pulver¬ 
izing  of  the  soil  before  the  crop  is  planted. 

The  growth  of  the  stem  of  plants  can  be  shown  in  a  similar  way  by 
tying  pieces  of  thread  around  the  stem  and  branches  of  any  plant  at 
intervals  of  one-fourth  inch,  or  marking  them  with  ink.  Measure 
carefully  from  time  to  time  the  distance  between  the  threads  and 
the  distance  from  the  top  thread  to  the  tip  of  the  plant  to  determine 
whether  the  stem  elongates  or  the  plant  makes  its  growth  mainly  at 
the  tip. 

Propagation. 

Plants  propagate  by  means  of  spores  (as  smut,  puffballs,  molds, 
ferns,  and  toadstools),  seeds  (corn,  bean,  and  lettuce),  root  sprouts 
(locust,  poplar,  and  plum),  and  by  division.  Some  of  the  plants 
which  propagate  by  division  divide  naturally  and  some  artificially. 
Natural  separation  of  parts  occurs  in  plants  which  reproduce  by 
means  of  rhizomes  or  root  stocks  (June  grass,  quick  grass,  and  iris), 
bulbs  (onion  and  lily),  corms  (crocus  and  gladiolus),  tubers  (potato, 
dahlia,  and  Jerusalem  artichoke),  detached  tips  of  branches  (water 
milfoil  and  some  varieties  of  willow),  stolons  (strawberry),  and 
layers  (black  raspberry  and  Forsythia).  Artificially  the  principal 
ways  of  propagating  plants  are  by  means  of  layers,  cuttings,  buds, 
and  grafts.  Many  of  the  plants  mentioned,  and  others  also,  propa¬ 
gate  in  two  or  three  different  ways. 

Have  pupils  try  experiments  in  tip  layering  with  black  raspberries 
(fig.  19),  in  vine  layering  with  grapevines  (fig.  20),  and  in  mound 
layering  with  currant  or  gooseberry  bushes  (fig.  21). 

Exercises  in  grafting  and  budding  can  be  conducted  indoors  to 
secure  facility  in  performing  these  operations  by  bringing  in  large 
branches  of  green  trees  for  stocks  and  securing  the  necessary  scions 
and  bud  sticks  in  the  usual  way.  The  stocks  may  be  prepared  for 
budding  by  boiling  to  loosen  the  bark,  and  trimmed  bud  sticks  may  be 
preserved  for  winter  use  in  dilute  alcohol.  The  pupils  should  be 
given  practice  in  as  many  methods  of  propagating  plants  as  possible. 

Exercise  10. — Spores. 

The  development  of  molds  from  spores  can  be  followed  easily  by 
cutting  a  potato  in  two,  rubbing  lightly  the  freshly  cut  surface  of  one 
half  with  a  piece  of  moldy  bread  and  putting  it  on  a  plate  under  an 

408 


20 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


inverted  tumbler.  Keep  this  covered  potato  in  a  warm  but  rather 
dark  place  for  several  days,  examining  it  every  few  hours  to  note 
progress  in  the  growth  of  the  mold. 

In  two  or  three  days  there  ought  to  be  a  heavy  growth  of  mold. 
By  examining  this  closely  the  pupils  will  be  able  to  see  little  globular 
spore  cases  growing  at  the  tops  of  slender  branches  which  spring 
up  from  a  network  of  whitish,  threadlike  material.  Observe  these 
spore  cases  closely  to  see  if  any  change  occurs  in  them  as  they  mature. 
Much  more  pleasure  can  be  had  from  the  study  of  molds  if  a  micro¬ 
scope  is  available,  but  all  that  has  been  mentioned  in  this  exercise 
can  be  seen  with  the  naked  eye. 

The  little  rusty  spots  seen  near  the  margins  of  some  fern  leaves  are 
spore  cases.  When  you  step  on  a  puffball  it  sends  up  a  cloud  of 
spores. 

Exercise  11. — Seeds — Germination  Test. 


Fig.  12.— Seed-testing  device. 


Count  out  50  or  100  seeds  of  the  kind  to  be  tested0  and  place  them 
in  a  plate  between  two  folds  of  moistened  canton  flannel  or  thin  blot¬ 
ting  paper  (fig.  12).  On  a  slip  of  white  paper  record  the  variety, 

number  of  seeds,  and 
the  date,  then  place 
it  on  the  edge  of  the 
plate.  Cover  the 
whole  with  another 
plate  or  a  pane  of 
glass  to  prevent  too 
rapid  evaporation  of  moisture.  Set  the  plate  in  a  warm  room  (68°  to 
86°  F.)  and  examine  the  seeds  every  twenty -four  hours  for  six  or  eight 
days.5  If  they  get  too  dry  add  enough  water  to  moisten,  not  satu¬ 
rate,  the  cloth  or  blotting  paper.  At  the  end  of  the  test  count  the 
sprouted  seeds  and  from  them  determine  what  percentage  of  the 
whole  number  of  seeds  is  good.  With  large  seeds  no  difficulty  will 
be  experienced  in  using  the  folds  of  canton  flannel,  but  with  small 
seeds  the  blotting  paper  is  better. 

Study  the  root  hairs,  which  will  show  plainly  if  dark-colored  cloth 
is  used  in  the  seed  tester. 


a  In  official  germination  tests  100  seeds  are  used  of  peas,  beans,  corn,  and  other 
seeds  of  similar  size,  and  200  seeds  of  clover,  timothy,  cabbage,  wheat,  and  other 
small  seeds. 

&  For  most  seeds  six  days  are  enough  for  the  test,  but  beets,  buckwheat,  cotton, 
cowpeas,  onions,  redtop,  tomatoes,  and  watermelons  should  be  allowed  to  remain 
eight  days;  salsify  and  spinach  ten  ciays;  carrots,  celery,  parsnips,  and  tobacco  four¬ 
teen  days,  and  blue  grass  and  parsley  twenty-eight  days. 

408 


21 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 

Exercise  12.— To  Make  a  Balance. 

A  balance  suitable  for  weighing  small  articles  can  be  made  easily 
and  cheaply.  Such  a  balance  can  be  made  sensitive  to  the  weight 
of  one-fourth  of  a  postage  stamp,  and  capable  of  sustaining  a  weight 
of  several  ounces.  It  is  made  chiefly  of  wood.  All  the  parts  are 
common  articles  and  only  ordinary  tools  are  required.  Only  certain 
features  require  careful  attention;  in  other  respects  rough  work  is 
permissible. 


The  essential  parts  of  a  balance  (see  fig.  13)  are  the  base  (a),  the 
pillar  (b),  the  beam  (c),  and  the  trays  or  pans,  as  they  are  usually 
called  (< d ,  d).  The  beam  is  balanced  by  means  of  the  balancing  nuts 
(e,  e).  The  pointer  (/)  indicates  on  the  scale  (g)  the  effect  of  weights 
on  the  trays.  A  screw  eye  ( h )  encircling  the  pointer  serves  to  hold 
the  beam  at  rest  or  permits  it  to  swing  as  desired,  according  as  the 
screw  eye  is  turned.  Four  screws  (i)  at  the  corners  of  the  base  serve  to 
level  the  balance. 

In  making  the  balance  thoroughly  dry,  soft,  pine  wood  is  prefer¬ 
able.  Screws  are  preferable  to  nails.  The  base  is  12  or  14  inches 

408 


22 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


long  by  7  inches  wide  and  1  inch  thick.  The  pillar  is  1  inch  square 
and  about  9  inches  high.  It  can  be  set  in  an  inch  hole  in  the  center 
of  the  base.  Care  should  be  taken  to  have  it  stand  perpendicular 
to  the  base.  The  upper  end  of  the  pillar  is  beveled  on  the  right 
and  left  sides,  as  shown  at  Ic.  A  slot  is  sawed  in  the  end  to  receive 
a  knife  edge,  as  shown  at  l .  The  beam  is  made  from  a  stick  1  inch 
square  and  about  10  inches  long.  Its  lower  face  is  left  straight; 
the  other  faces  are  beveled  from  the  center  to  the  ends,  which  are 
left  three-eighths  or  one-half  inch  square.  A  notch  1  inch  wide 
and  one-half  inch  deep  is  accurately  cut  in  the  center  of  the  flat  or 
bottom  face.  This  receives  the  central  bearing  (m)  of  the  beam. 
An  inch  from  each  end  of  the  beam  a  notch  one-fourth  inch  deep 
is  cut  to  receive  the  tray  bearings.  Each  end  is  rounded  to  receive 
the  balancing  nuts.  The  nuts  should  cut  well-defined  threads  in 
the  wood  and  move  easily  and  smoothly.  Applying  a  little  soap 
to  the  threads  helps  this.  A  strong  pointer  (/)  is  firmly  fastened 
to  the  beam  by  two  or  more  screws.  Its  lower  end  is  provided  with 
a  needle,  colored  black  so  as  to  be  readily  seen.  The  screw  eye  ( Ji ) 
is  placed  near  the  end  of  the  pointer  and  in  the  center  of  the  pillar. 
It  should  turn  easily  and  smoothly.  When  the  balance  is  otherwise 
completed,  turn  the  screw  eye  so  as  to  hold  the  pointer  firmly,  then 
paste  to  the  pillar  back  of  the  pointer  a  strip  of  white  paper  ( g ) 
bearing  scale  marks  one-sixteenth  inch  apart,  with  the  0  mark  of 
the  scale  directly  back  of  the  needle. 

The  three  bearings  of  the  beam  are  the  most  exacting  features  of 
the  construction.  Each  consists  of  a  knife  edge  acting  within  a 
groove  formed  of  bent  tin.  The  knife  edge  (Z)  for  the  central  bearing 
may  be  made  of  a  pocket  or  case  knife  blade  or  of  a  piece  of  hard 
brass  filed  to  a  straight,  sharp  edge.  The  knife  edges  for  the  end 
bearings  are  made  by  filing  the  lower  side  of  the  tray  wires  where 
they  cross  the  beam,  producing  a  straight,  sharp  edge  (n)  about 
three-fourths  inch  long.  The  tins  forming  the  grooves  of  the  bear¬ 
ings  are  made  of  thin  tin,  such  as  is  used  in  oyster  and  vegetable 
cans.  Bright  pieces  are  selected.  The  central  bearing  requires  a 
strip  1  inch  wide  and  2  inches  long  (m).  It  is  bent  across  at  the 
middle,  the  bend  being  lightly  hammered  flat  on  a  flatiron.  The 
ends  are  then  separated.  The  halves  of  the  strip  curve  somewhat, 
leaving  a  narrow  angle  at  the  bend.  This  tin  is  firmly  held  in  the 
central  notch  of  the  beam  by  four  small  screws.  The  tin  strips 
for  the  end  bearings  are  about  one-half  inch  wide.  They  are  bent 
in  the  same  way  as  the  other.  One  end  of  the  strip  is  longer  than 
the  other,  and  is  punched  to  receive  a  single  screw  holding  it  to  the 
beam,  as  shown  at  o.  The  bending  of  the  tin  strips  roughens  the 
surface  of  the  groove.  It  must  be  polished  by  rubbing  the  back 

408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


23 


of  the  point  of  a  knife  blade  back  and  forth  in  the  groove  for  some 
time.  To  insure  success  the  grooves  must  be  very  narrow  to  prevent 
side  slipping,  yet  not  so  narrow  as  to  bind  on  the  knife  edge.  The 
highly  polished  groove  and  sharp  knife  edges  produce  the  least 
friction  and  increase  the  sensitiveness  of  the  balance. 

The  tray  wires  are  made  of  common  No.  12  wire.  The  trays  are 
3  by  3  inches  and  one-fourth  inch  thick.  Two  holes  near  opposite 
edges  receive  the  wires,  which  are  bent  in  opposite  directions  beneath 
the  trays,  thereby  holding  them  firm  and  level.  If  the  trays  tend 
to  swing  from  front  to  back  of  the  balance,  the  tins  of  the  bearings 
may  be  slightly  twisted  by  inserting  a  knife  blade  under  them. 

The  balance  can  now  be  tested  for  use.  When  in  working  con¬ 
dition  the  pointer  will  slowly  swing  back  and  forth  many  times  and 
finally  come  to  rest  at  0  of  the  scale.  It  probably  will  not  do  this  at 
the  first  trial.  Set  the  balancing  nuts  at  about  equal  distances  from 
the  ends  of  the  beam,  then  stand  tacks  along  the  lighter  beam  arm 
until  the  two  arms  nearly  balance.  The  tacks  are  then  driven  in 
permanently.  If  tacks  are  too  light,  use  brads  or  screws.  The 
final  balancing  can  then  be  done  by  properly  moving  one  or  both 
of  the  nuts.  The  proper  adjustment  of  the  balancing  nuts  should  be 
tested  each  time  the  balance  is  used. 

Weights  and  objects  to  be  weighed  can  be  held  on  the  trays  by 
cardboard  dishes  (j).  A  pair  of  forceps  can  be  made  from  a  strip 
of  spring  brass  or  even  of  hickory  wood,  the  points  being  properly 
sharpened. 

A  set  of  metric  weights  ranging  from  20  grams  to  1  centigram  and 
suitable  for  use  with  this  balance  can  be  had  for  SI  or  less. 

Exercise  13.— Seeds — Purity  Test. 

It  is  as  important  to  plant  pure  seeds  as  it  is  to  plant  seeds  that 
will  grow.  Many  of  the  smaller  seeds,  such  as  clovers  and  grasses, 
frequently  contain  seeds  of  troublesome  weeds  and  inert  material 
like  chaff,  sticks,  broken  seeds,  etc. 

To  make  a  purity  test,  secure  one  or  more  samples  of  red  clover, 
alsike  clover,  or  alfalfa  seed,  preferably  of  different  trade  grades, 
and  examine  them  for  impurities.  Mix  the  seed  thoroughly  and 
weigh  out  5  grams  of  the  mixture.  Spread  this  sample  thinly  on  a 
piece  of  white  paper.  By  means  of  a  magnifying  glass  (fig.  14)  sepa¬ 
rate  the  seed  with  a  knife  blade  into  three  parts — one  containing  only 
pure  seed  of  the  kind  being  tested,  another  consisting  of  seeds  other 
than  pure  seed,  as  adulterants  or  weed  seeds,  and  the  third  consisting 
of  inert  materials,  as  sticks,  gravel,  broken  seeds,  etc.  By  weighing 
these  parts  separately  and  comparing  their  weights  with  that  of  the 
original  sample  the  percentage  each  of  pure  seeds,  of  weed  seeds,  and 

408 


24 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


of  inert  materials  is  readily  determined.  Slight  loss  in  weight  dur¬ 
ing  careful  testing  is  usually  due  to  the  loss  of  fine  inert  matter. 

It  is  sometimes  important  to  know  the  character  of  the  foreign 
seeds.  If  an  adulterant  like  yellow  trefoil  is  present,  it  should  be 
recognized.  It  may  be  of  interest  to  determine  its  amount  separately. 
Certain  weed  seeds  are  especially  undesirable,  as  dodder,  Canada 
thistle,  chicory,  wild  carrot,  etc.  If  present,  these  should  be  counted 
and  their  number  per  pound  estimated  according  to  the  weight  of 
the  sample  tested.  Farmers’  Bulletins  260  and  382  will  be  helpful  in 
determining  adulterants  and  weed  seeds. 

The  pure  seed  may  contain  many  shriveled  seeds.  It  would  be  of 
interest  to  know  how  the  weight  of  100  of  these  seeds  compares  with 
that  of  an  ecpial  number  of  plump  seeds.  A  question  may  arise  as 


Fig.  14.— A  serviceable  tripod  magnifying  glass  and  a  convenient  mount  for  preserving  seeds  for  study. 

to  the  value  of  such  shriveled  seed.  Again,  the  relative  weights  of 
the  smallest  and  largest  seeds  in  the  sample  may  be  determined. 
See  how  equal  numbers  of  large  and  small  seeds  compare  in  weight. 

It  may  be  well  to  consider  the  relative  chances  of  large  and  small 
seeds  in  producing  a  crop  under  adverse  seeding  and  weather  con¬ 
ditions.  If  the  pure  seed  consists  in  part  of  bright  seed  and  in  part 
of  dull,  reddish-brown  seeds,  it  is  evidently  a  mixture  of  new  and  old 
seed.  Make  a  number  of  germinating  tests  to  determine  these  matters. 

In  making  a  germinating  test  of  such  seed  the  seeds  to  be  tested 
are  counted  indiscriminately  from  the  pure  seed  lot. 

It  is  of  especial  interest  in  such  tests  to  consider  the  different  trade 
grades  offered  by  large  dealers.  After  making  complete  tests  of 
different  grades  compare  their  quality  with  their  price,  bearing  in 

408 


25 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 

mind  that  more  than  95  per  cent  of  the  sample  should  be  pure  seed 

and  more  than  95  per  cent  of  the  pure  seed  should  terminate 
promptly. 

Exercise  14.— Development  of  Young  Plants  from  Seeds. 

The  development  of  young  plants  from  seeds  may  be  observed 
very  nicely  by  planting  seeds  against  the  sides  in  tall  bottles  or  in  a 
box  with  glass  sides,  as  shown  in  figures  15  and  16.  Suppose,  for 
example,  that  you  put  an  inch  of  soil  in  the  bottom  of  the  box  shown 
in  figure  15  and  then  put  a  kernel  of  corn  on  top  of  the  soil  close  to 
the  glass  at  one  end  of  the  box  and  a  bean  at  the  other  end  of  the  • 


box.  Then  put  in  another  inch  of  soil,  another  kernel  of  corn,  an¬ 
other  bean,  and  perhaps  also  a  clover  seed  near  the  glass  in  the 
middle  of  the  box.  Continue  in  this  way  until  the  box  is  filled. 
Water  the  soil  thoroughly,  cover  the  glass  sides  of  the  box  with 
black  cloth  or  paper  to  exclude  the  light,  and  set  it  aside  to  allow  the 
seeds  to  germinate. 

You  will  doubtless  find  that  some  very  large  seeds  will  germinate 
and  send  leaves  to  the  surface  from  a  depth  of  5  or  6  inches  in  a  light 
sandy  soil,  but  that  this  depth  is  not  so  favorable  for  their  develop¬ 
ment  as  a  depth  of  2  or  3  inches.  Try  to  find  the  best  depth  for 
planting  a  few  large  seeds  and  a  few  small  seeds  like  radishes,  clover, 

408 


26 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


lettuce,  etc.  Planting  seeds  against  the  side  of  the  glass  in  this 
way  will  enable  you  and  the  pupils  to  examine  them  from  time  to 
time  and  see  what  becomes  of  those  which  do  not  reach  the  surface. 


Exercise  15. — To  Show  that  Young  Plants  Get 

Food  from  Seeds. 

Much  of  the  food  of  very  young  plants  comes 
from  the  seeds  to  which  they  are  attached. 
To  prove  this,  plant  two  beans  in  a  tin  can  con¬ 
taining  sandy  soil;  water  and  keep  in  a  warm, 
light  place.  Soon  after  the  beans  push  above 
ground  take  a  sharp-pointed  knife  and  carefully 
cut  off  the  two  half  beans  (cotyledons)  without 
injuring  the  rest  of  the  plant.  (See  A,  fig.  17.) 
Allow  the  plants  to  grow  for  a  week  or  two  and 
note  the  more  rapid  development  of  the  plant 
to  which  the  cotyle¬ 
dons  are  attached. 

Have  the  children 
try  similar  experi¬ 
ments  at  home  with 
squash  seeds  or  Lima 
beans. 

Exercise  16. — Pollina¬ 
tion. 

Fig.  16.— To  show  the  best 

depths  at  which  to  plant  (^)  Why  do  some 

flowers  produce  fruit 
or  seed  while  others  do  not?  Why  do 
some  ears  of  corn  have  vacant  places  on 
the  cob — places  where  there  are  no 
kernels?  This  can  be  answered  by  an 
experiment  in  the  school  or  at  home. 

Find  a  hill  of  corn  on  which  an  ear  is  just 
starting,  and  before  any  silk  pushes  out 
of  the  husk  tie  a  paper  or  muslin  bag 
over  the  ear  in  such  a  way  as  to  exclude 
all  pollen  and  insects.  Leave  this  on  for 
several  weeks;  then  examine  the  ear  to 
see  if  anv  kernels  of  corn  have  de- 
veloped.  The  application  of  pollen  to 
the  pistil  of  a  flower  is  called  pollination. 

The  necessity  of  pollination  for  the  production  of  fruit  can  be 
shown  by  another,  somewhat  more  difficult,  experiment.  Carefully 
open  the  flower  bud  of  an  apple,  a  tomato,  or  other  flower  having 

408 


Fig.  17. — Plant  food  in  seeds.  After 
Graham,  Ohio  Agr.  Col.  Ext.  Bui., 
Vol.  I,  No.  8,  p.  10.  Beans  planted  in 
rich  black  earth  on  the  same  day. 
Both  plants  came  up  on  the  same 
day.  The  half  beans  were  removed 
from  one.  The  other  grew  faster  be¬ 
cause  the  half  beans  furnished  food. 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


27 


both  stamens  and  pistil,  when  it  appears  to  be  just  ready  to  blossom, 
and  remove  all  of  the  stamens,  using  care  not  to  injure  the  pistil  or 
stigma  (fig.  18) .  Without  removing  the  flowers  from  the  parent  plant 
inclose  all  of  them  in  small  white  muslin  bags  in  such  way  that  no 
insects  can  get  in.  At  the  same  time  prepare  other  flowers  of  the 
same  kind  in  the  same  way,  except  that  pollen  from  another  flower 
of  the  same  kind  is  in  each  case  dusted  on  the  pistil  of  the  flower 
inclosed.  After  a  week  or  ten  days  remove  the  bags  and  see  what  has 
happened  to  the  flowers.  You  will  probably  find  that  all  of  the  flow¬ 
ers  not  dusted  with  pollen  have  withered  and  dropped  off  without 
producing  any  fruit,  while  the  others  have  begun  to  develop  small 
fruits. 

From  this  it  will  be  seen  that  it  is  necessary,  in  order  for  a  flower 
to  produce  fruit,  that  its  pistil  receive  pollen  either  from  the  same 
flower  or  from  some  other  closely  related  flower.  This  pollen  is 
carried  by  the  wind  and  by  bees,  flies,  and  other  insects,  but  some- 


Fig.  18.— Tomato  blossom  ready  to  pollinate.  At  the  left  a  partly  opened  bud,  in  the  middle  an  opened 
blossom,  at  the  right  an  opened  blossom  with  anthers  removed. 


times  none  of  these  agencies  succeed  in  bringing  the  right  kind  of 
pollen  to  the  flower,  and  it  withers  and  drops  off. 

In  the  case  of  corn  each  silk  protruding  from  the  husks  is  a  pistil, 
and  if  any  one  of  these  silks  fails  to  receive  pollen  the  kernel  of  corn 
down  at  the  lower  end  of  the  silk  will  not  be  developed. 

(B)  Have  the  children  plant  a  few  hills  each  of  field  corn  and  pop 
corn  side  by  side  in  the  school  garden  or  at  home.  In  the  autumn 
when  the  corn  is  husked  notice  the  mixture  of  two  kinds  of  kernels 
on  the  same  cob.  How  did  the  corn  mix  ?  It  is  by  putting  the  pollen 
of  one  kind  of  plant  on  the  pistil  of  another  closely  related  and 
excluding  all  other  pollen  that  plant  breeders  sometimes  originate 
new  varieties. 

Exercise  17. — Layering. 

Layering  may  be  considered  the  connecting  link  between  natural 
and  artificial  propagation.  Many  plants,  such  as  black  raspberries, 
grapes,  Forsytliias,  and  others,  increase  naturally  in  this  way,  but 

408 


28 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


man  has  lent  his  aid  in  so  many  ways  to  this  process  of  propagation 
that  it  may  he  considered  to  a  certain  extent  artificial. 

A  layer  is  a  branch  so  placed  in  contact  with  the  earth  as  to  induce  it 
to  throw  out  roots  and  shoots,  thus  producing  one  or  more  independ¬ 
ent  plants,  the  branch 
meanwhile  remaining  at¬ 
tached  to  the  parent 
plant.  Layering  fre¬ 
quently  proves  a  satis¬ 
factory  method  of  multi- 
plying  woody  plants 
which  do  not  readily 
take  root  from  cuttings. 

Tip  layering. — The  tip 
of  a  branch  or  cane  is 
fig.  19.— Tip  layering.  bent  down  to  the  ground 

and  slightly  covered 
with  soil,  when  it  will  throw  out  roots  and  develop  a  new  plant  (fig. 
19).  Many  plants  can  be  propagated  in  this  way.  The  black  rasp¬ 
berry  is  a  familiar  example. 

Vine  layering. — A  vine  is  stretched  along  the  ground  and  buried 

throughout  its  entire  length  in  a  shallow 
trench,  or  it  may  be  covered  in  certain 
places,  leaving  the  remaining  portions 
exposed.  Roots  will  be  put  forth  at 
intervals  and  branches  thrown  up. 
Later  the  vine  may  be  cut  between 
these,  leaving  a  number  of  independent 
plants  (fig.  20).  The  grape  can  be 
easily  propagated  in  this  way. 

Mound  layering. — Plants  which  stool, 


Fig.  20. — Vine  layering. 


sending  up  a  large  number  of  stems  or  shoots  from  a  single  root,  are 
often  layered  by  mounding  up  the  earth  so  as  to  cover  the  bases  of 
these  stems  and  cause  them  to  throw  out  roots  (fig.  21).  Each  may 
then  be  removed  from  the  original  root  and  treated  as  an  independent 


408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


29 


plant.  A  plant  is  often  cut  back  to  the  ground  to  make  it  send  up 
a  large  number  of  shoots  to  be  layered  in  this  way. 


Facilities  for  Rooting 
Cuttings. 

In  order  successfully  to 
root  cuttings  of  coleus, 
geraniums,  fuchsias,  roses, 
and  begonias  in  the  school¬ 
room  it  will  be  an  advant¬ 
age  to  have  a  broad  window 
box  constructed  some¬ 
what  as  follows:  Make  a 
frame  about  15  or  20 
inches  wide,  8  inches  high 
at  one  side  and  12  inches 
high  at  the  other,  and  as 
long  as  the  width  of  the 


Fig.  21.— Mound  layering. 


window  in  which  it  is  to  be  used.  Place  a  tight  bottom  in  the  frame, 
thus  making  a  box  similar  to  that  shown  in  figure  22.  Provide 


three  or  four  holes  one-half  inch  in 


to 

diameter  in  the  bottom  of 
the  box  to  allow  the  escape 
of  any  excess  moisture.  Place 
about  1  inch  of  broken  pots, 
coarse  gravel,  or  clinkers  in 
the  bottom  of  the  box,  and 
on  top  of  these  place  a  layer 
of  clean  sand  free  from 
clay  or  decaying  organic 
matter,  about  2\  to  3  inches 
thick.  Over  the  top  place 
panes  of  glass,  so  as  to 
make  a  close  but  well-lighted 
chamber  within  the  frame. 
Place  the  cuttings  in  this 
frame.  By  using  care  in 
watering  and  providing  ven¬ 
tilation  by  the  partial  re¬ 
moval  of  the  glass  as  neces¬ 
sity  requires  under  such 
treatment,  lair  results  should 
follow.  Some  experience  will 
be  necessary  to  successfully  root  plants  even  with  this  device,  but 
much  better  results  may  be  expected  than  without  it. 

40S 


Fig.  22.— Frame  for  rooting  cuttings. 


30 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


Exercise  18. — To  Make  Soft  Cuttings. 

Soft  cuttings  may  be  made  from  either  the  leaf  or  stem.  Some 
plants,  such  as  the  Rex  begonia  and  wax  plants,  may  be  propagated 

by  inserting  the  edge  of  a  leaf  or  even  a  piece 
of  a  leaf  (fig.  23)  in  sand  and  supplying  it  with 
plenty  of  moisture  and  warmth;  or  a  leaf  may 
be  laid  flat,  right  side  up,  on  the  surface  of  the 
sand  and  fastened  down  by  splinters  through 
the  veins  at  intervals  (fig.  24).  Plants  will 
spring  up  at  the  broken  edges  of  the  leaf  or  at 
cut  places  in  the  veins. 

Stem  cuttings  are  readily  made  from  the  coleus, 
geranium,  verbena,  tomato,  and  numerous  other 
herbaceous  plants.  Take  thrifty  shoots  from 
any  of  these  plants  and  divide  them  into  cut¬ 
tings  having  at  least  two  nodes  and  several 
leaves;  reduce  the  leaf  surface  to  about  one-half 
to  check  evaporation;  insert  the  cutting  in  moist 
sand  about  one-half  of  its  length  and  press  the 
sand  firmly  around  it.  (See  fig.  25.) 

Exercise  19. — To  Make  Hard  Cuttings. 

Hard  cuttings  may  be  made  from  dormant 
mature  wood  of  last  season's  growth  of  privet,  grape,  barberry, 
willow,  and  many  other  plants.  Make  the  cuttings  4  to  6  inches 
long  so  as  to  include  at  least  two  nodes.  They  may  then  be  rooted 


Fig.  24. — Leaf  cutting— whole  leaf. 


in  the  same  way  that  soft  cuttings  are  rooted,  or,  if  prepared  in 
autumn  or  winter  for  planting  out  of  doors  next  spring,  they  may 
be  tied  in  bundles  of  about  50,  using  care  to  keep  all  tips  in  one 
direction  and  butts  in  the  other.  These  bundles  should  be  buried 


Fig.  23.— Leaf  cutting— part 
of  leaf. 


408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


31 


out  of  doors  or  put  in  moist  sand  or  sawdust  in  the  cellar,  placing 
tips  down.  In  the  spring  prepare  a  trench  in  sand  or  sandy  loam, 
as  shown  in  figure  26,  set  in  the  cuttings  about  6  inches  apart,  and 

pack  earth  tightly  around  them. 
Keep  the  surface  of  the  soil 
free  from  weeds  and  mellow 
throughout  the  summer,  water 
in  dry  times,  and  it  is  likely 


Fig.  25.— Stem  cutting  or  “slip”  of  coleus.  Fig.  26. — Cutting  set  in  trench. 

that  a  large  percentage  of  the  cuttings  will  root  and  grow.  There  are 
various  modifications  of  the  simple  cutting,  as  shown  in  figure  27. 


Fig.  27.— Cuttings:  a,  Simple  cutting;  b,  heel  cutting;  c,  mallet  cutting;  d,  single-eye  cutting. 


Exercise  20. — To  Make  Grafting’  Wax. 

A  good  grafting  wax  may  be  made  of  the  following  ingredients: 
Kesin,  4  parts;  beeswax,  2  parts;  tallow  or  linseed  oil,  1  part  by 

408 


32 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


weight.  If  a  harder  wax  is  needed,  5  parts  of  resin  and  2\  of  bees¬ 
wax  may  be  used  with  1  part  of  tallow. 

The  resin  and  beeswax  should  be  broken  up  tine  and  melted 
together  with  the  tallow.  When  thoroughly  melted  the  liquid 
should  be  poured  into  a  vessel  of  cold  water.  As  soon  as  it  becomes 
hard  enough  to  handle  it  should  be  taken  out  and  pulled  and  worked 
until  it  becomes  tough  and  has  the  color  of  very  light-colored  manila 
paper.  If  the  wax  is  applied  by  hand,  the  hands  should  be  well 
greased,  tallow  being  the  best  material  for  this  purpose.  The  wax 
may  be  applied  hot  with  a  brush,  but  care  is  necessary  in  order  to 
avoid  injury. 

The  wax  should  be  spread  carefully  over  all  cut  or  exposed  surfaces 
and  pressed  closely,  so  that  upon 
cooling  it  will  form  a  sleek  coat¬ 
ing  impenetrable  to  air  or  moisture. 

Waxed  string  may  be  prepared 
by  putting  a  ball  of  No.  18  knit¬ 
ting  cotton  into  a  kettle  of  melted 
grafting  wax.  In  five  minutes  it 


a 

Fig.  29.— Cleft  grafting:  a,  Scion;  b,  scions  inserted 
Fig.  28. — Grafting  tool.  in  cleft. 

will  be  thoroughly  saturated,  after  which  it  will  remain  in  condition 
for  use  indefinitely. 


Exercise  21. — Cleft  Grafting. 

To  make  a  cleft  graft  select  a  branch  1  or  1£  inches  in  diameter 
and  sever  it  with  a  saw.  Care  should  be  taken  that  the  bark  be  not 
loosened  from  any  portion  of  .the  stub.  Split  the  exposed  end  with  a 
broad  thin  chisel  or  grafting  tool  (fig.  28).  Then  with  a  wedge  or 
the  wedge-shaped  prong  at  the  end  of  the  grafting  tool  spread  the 
cleft  so  that  the  scion  (fig.  29,  a)  may  be  inserted  (fig.  29,  b). 

408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION.  33 

The  scion  should  consist  of  a  portion  of  the  previous  season’s 
growth  of  the  tree  to  be  propagated  and  should  be  long  enough  to 
have  two  or  three  buds.  The  lower  end  of  the  scion,  which  is  to  be 
inserted  into  the  cleft,  should  be  cut  into  the  shape  of  a  wedge, 
having  the  outer  edge  thicker  than  the  other  (fig.  30).  In  general 
it  is  a  good  plan  to  cut  the  scion  so  that  the  lowest  bud  will  come 
just  at  the  top  of  this  wedge  (fig.  29,  a)  in  order  that 
it  will  be  near  the  top  of  the  stock.  The  advantage 
of  cutting  the  wedge  thicker  on  one  side  is  illus¬ 
trated  in  figure  30,  which  shows  how  the  pressure  of 
the  stock  is  brought  upon  the  outer  growing  parts 
of  both  scion  and  stock,  whereas  were  the  scion 

....  . .  .  i  • ,  •  .  .  .  Fig.  — Cross  section  of 

thicker  on  the  inner  side  the  conditions  would  be  re-  stock  and  scion, 

versed,  and  the  death  of  the  scion  would  follow. 

The  importance  of  having  an  intimate  connection  between  the 
growing  tissues  of  both  scion  and  stock  can  not  be  too  strongly 
emphasized,  for  upon  this  alone  the  success  of  grafting  depends. 
To  make  this  contact  of  the  growing  portions  doubly  certain,  the 
scion  is  often  set  at  a  slight  angle  with  the  stock  into  which  it  is 
inserted,  in  order  to  cause  the  growing  portions  of  the  two  to  cross. 

After  the  scions  have  been  set, 
the  operation  of  cleft  grafting  is 
completed  by  covering  all  cut  sur¬ 
faces  with  a  layer  of  grafting  wax. 

Cleft  grafting  is  particularly 
adapted  to  top-working  old  trees, 
that  is,  changing  them  from  un¬ 
desirable  to  desirable  varieties. 
Branches  too  large  to  be  worked  by 
other  methods  can  be  cleft  grafted. 
Sometimes  several  varieties  are 
grafted  on  a  single  tree.  The  best 
time  for  cleft  grafting  is  in  the  spring 
just  after  growth  has  begun.  Wood 
for  scions  is  usually  cut  in  the  fall, 
tied  in  bundles,  and  buried  in  sand  to 
protect  them  from  extremes  of  heat 
and  cold  until  they  are  to  be  used. 

Exercise  22. — Whip  Grafting-. 

To  make  a  whip  graft,  cut  the  stock  off  diagonally — one  long 
smooth  cut  with  a  sharp  knife,  leaving  about  three-fourths  of  an 
inch  of  cut  surface,  as  shown  in  figure  31,  a.  Place  the  knife  about 
one-third  of  the  distance  from  the  end  of  the  cut  surface,  at  right 


V  >' 


Fig.  31.— Whip  grafting:  a,  The  stock;  b,  the 
scion;  c,  stock  and  scion  united. 


408 


34 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


angles  to  the  cut,  and  split  the  stock  in  the  direction  of  its  long  axis. 
Cut  the  lower  end  of  the  scion  in  like  manner  (fig.  31,  a  and  &),  and 
when  the  two  parts  are  forced  together,  as  shown  in  figure 
31,  c,  the  cut  surfaces  will  fit  neatly,  and  one  will  nearly 
cover  the  other  if  the  scion  and  stock  are  of  the  same  size. 
A  difference  in  diameter  of  the  two  parts  to  be  united  may 
be  disregarded  unless  it  be  too  great.  After  the  scion  and 
stock  have  been  joined  they  should  be  wrapped  with  5  or 
6  turns  of  waxed  cotton  to  hold  the  parts  firmly. 

This  is  the  process  used  almost  exclusively  in  the  pro¬ 
duction  of  young  nursery  stock  by  means  of  root  grafting. 

The  roots  are  dug  and  the  scions  are  cut  in  the  autumn 
and  stored.  The  work  of  grafting  may  be  done  during  the 
winter  months.  When  the  operation  has  been  completed 
the  grafts  are  packed  away  in  moss,  sawdust,  or  sand,  in  a 
cool  cellar,  to  remain  until  spring.  It  is  important  that  the 
place  of  storage  be  cool,  else  the  grafts  may  start  into 
growth  and  be  ruined,  or  heating  and  rotting  may  occur. 
If  the  temperature  is  kept  low— not  above  40°  F. — there 
will  be  no  growth  except  callousing  and  the  knitting 
together  of  stock  and  scion.  In  spring  the  grafted  plant 
is  so  set  as  to  bring  the  union  of  stock  and  scion  below  the 
surface  of  the  ground. 

Top-grafting  may  also  be  done  in  this  way,  but  whenever  the 
union  is  above  ground  it  must  be  protected,  as  in  cleft  grafting,  by 
either  a  coating  of  grafting  wax  or 
a  bandage  of  waxed  muslin. 


Fig.  32. — A 
bud  stick. 


Fig.  33.— Cutting  the  bud. 


Fig.  34.— Budding:  Preparing  the  stock. 


Exercise  23. — Budding. 

Budding  is  one  of  the  most  rapidly  performed  and  economical  forms 
of  artificial  propagation.  The  work  of  budding  is  done  during  the 

408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


35 


season  of  active  growth — July,  August,  or  early  September.  The 
bud  should  be  taken  from  strong,  healthy  twigs  of  the  present  season’s 
growth.  The  bud  sticks  (fig.  32)  are  prepared  so  that  the  petiole  or 
stem  of  each  leaf  is  left  attached  to  serve  as  a  handle  to  aid  in  inserting 
the  bud  beneath  the  bark  of  the  stock.  The  bud  should  be  cut  as  in 
figure  33,  paring  off  a  small  portion  of  the  woody  tissue  with  the  bud. 

The  stock  for  budding  should  be  at  least  as  thick  as  an  ordinary 
lead  pencil.  With  the  apple  and  pear  a  second  season’s  growth  will 
be  necessary  to  develop  this  size,  while  with  the  peach  a  single  season 
will  suffice.  To  bud  a  plant  make  a  T-shaped  cut  through  the  bark 
for  the  reception  of  the  bud,  as  shown  in  figure  34,  a. 

Loosen  the  flaps  of  bark  caused  by  the  intersection  of  the  two  cuts 
(fig.  34,  b)  with  the  ivory  heel  of  the  budding  knife,  grasp  the  bud  by 


Fig.  35.— Budding:  a,  Inserting  the  bud;  b,  tying;  c,  cutting  off  the  top. 


the  leaf  stem  as  a  handle,  insert  it  under  the  flaps,  and  push  it  firmly 
in  place  until  its  cut  surface  is  entirely  in  contact  with  the  peeled  body 
of  the  stock  (fig.  35,  a).  Tie  a  ligature  tightly  about  it,  above  and 
below  the  bud,  to  hold  it  in  place  until  a  union  shall  be  formed  (fig. 
35,  b).  Bands  of  raffia  or  wrapping  cotton,  about  10  to  12  inches 
long,  make  a  most  convenient  tying  material.  As  soon  as  the  buds 
have  united  with  the  stock  the  ligature  should  be  cut  in  order  to 
prevent  girdling  the  stock.  This  done,  the  operation  is  complete 
until  the  following  spring,  when  all  the  trees  in  which  the  buds  have 
1  ‘taken”  should  have  the  top  cut  off  just  above  the  bud  (fig.  35,  c), 

408 


36 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


PART  2.— THE  ENVIRONMENT  OF  THE  PLANT. 

Exercise  24. — Conditions  Essential  to  Plant  Growth. — Light. 

To  show  that  light  is  an  important  factor  in  plant  growth  call  the 
attention  of  the  pupils  to  the  way  in  which  plants  growing  in  a 
poorly  lighted  room  stretch  toward  the  nearest  window.  Recall  how 
potatoes  sprouting  in  the  cellar  send  their  sprouts  sometimes  for  a 
yard  or  more  in  the  direction  of  the  light.  Notice  the  struggle  of 
forest  trees  to  send  their  branches  up  to  the  light.  There  will  be 
exceptions,  of  course — some  trees  and  shrubs  which  seem  to  do  well 
under  the  cover  of  other  trees,  but  in  the  main  those  trees  which  are 
siiut  off  from  the  direct  rays  of  the  sun  do  not  thrive.  It  will  be  an 
instructive  object  lesson  to  visit  a  forest  and  notice  how  on  the  edge 
of  the  woods  the  large  limbs  on  all  of  the  trees  are  on  the  side  next 
to  the  open  field.  Why  do  trees  growing  in  the  thick  forest  become 
so  much  taller  and  more  spindling  than  trees  of  the  same  variety 
growing  in  the  open  field  ?  Does  this  habit  of  trees  have  any  im¬ 
portant  economic  bearing  ?  Are  trees  with  long,  straight,  clean 
trunks  more  or  less  valuable  for  timber  than  trees  with  low,  bushy 
tops  ? 

The  influence  of  light  on  plant  growth  may  be  shown  experi¬ 
mentally  as  follows:  Plant  two  pots  with  corn.  Place  one  in  a 
window  where  it  may  make  a  normal  growth.  Give  the  other  the 
same  temperature  and  the  same  attention  as  regards  watering,  but 
place  it  under  a  paper  cone  or  box  through  which  light  can  not  pene¬ 
trate.  Contrast  the  appearance  of  the  two  sets  of  plants  grown  under 
these  conditions.  After  the  plants  under  the.  cone  or  box  have 
attained  a  height  of  2  or  3  inches,  remove  the  covering  and  note 
what  takes  place  when  the  pot  is  placed  in  full  sunshine. 

Exercise  25. — Conditions  Essential  to  Plant  Growth. — Heat. 

Numerous  opportunities  will  occur  to  show  the  importance  of  heat 
as  a  factor  in  plant  growth.  Seeds  may  be  planted  in  two  pots  or 
tin  cans  which  are  treated  exactly  alike  in  every  way  except  that 
one  pot  is  kept  where  the  temperature  ranges  from  60  to  80°  F.,  while 
the  other  is  kept  in  a  temperature  20  to  40°  cooler.  The  latter  may 
germinate,  but  there  will  be  a  marked  difference  in  the  time  of  germi¬ 
nation  and  in  the  vigor  of  the  plants. 

In  the  spring  or  fall  when  the  weather  is  cool,  but  not  frosty,  radish 
seeds  may  be  started  indoors  in  two  boxes  about  a  foot  square  and  8 
or  10  inches  deep,  with  3  inches  of  good  soil  in  the  bottom.  As  soon 
as  the  young  plants  are  well  started  remove  all  but  5  or  6  of  the 
strongest  plants  in  each  box,  then  set  the  boxes  side  by  side  out  of 
doors.  Cover  one  box  with  a  pane  of  glass,  leaving  a  small  crack  for 

408 


SCHOOL  EXEKCISES  IN  PLANT  PKODUCTION. 


37 


ventilation,  but  aside  from  this  treat  them  exactly  alike.  Water 
when  necessary.  Put  a  thermometer  in  each  box  in  such  a  position 
that  temperatures  can  be  read  without  disturbing  the  boxes.  Take 
and  record  temperatures  several  times  daily  for  a  week  and  observe 
differences  in  the  development  of  the  plants.  Draw  conclusions  con¬ 
cerning  the  relation  of  heat  to  the  growth  of  plants. 

Exercise  26. — Conditions  Essential  to  Plant  Growth — Moisture. 

Take  two  pots  or  tin  cans  in  which  plants  are  growing.  Put  them 
under  like  conditions  except  that  water  is  withheld  from  one  for  sev¬ 
eral  days.  Have  pupils  draw  conclusions  as  to 
the  importance  of  moisture  to  plant  growth. 

Exercise  27. — Conditions  Essential  to  Plant 

Growth— Air. 

Air  is  necessary  in  the  soil  in  order  to  make  it 
a  congenial  place  for  the  growth  of  plants. 

(A)  The  necessity  for  air  can  be  demonstrated  fig.  36.— Method  of  demon- 
very  nicely  by  taking  some  ordinary  garden  strating  the  effec<;  of  t0° 
soil  which  is  rather  retentive  in  nature — that  is, 

contains  a  considerable  percentage  of  clay — and  placing  an  equal 
quantity  in  each  of  two  tumblers,  as  shown  in  figure  36.  In  one  plant 
seeds  of  beans  or  peas  in  the  usual  fashion,  and  in  the  other  plant  the 

same  kind  of  seeds  in  the  same  way,  but 
keep  the  soil  constantly  saturated  with 
water,  so  that  there  is  a  thin  stratum  of 
moisture  over  the  surface  of  the  soil.  The 
seeds  in  the  first  tumbler  will  undoubtedly 
germinate  in  a  short  time,  while  the  seeds 
in  the  other  tumbler  will  require  a  longer 
time  to  germinate,  and  if  the  temperature 
of  the  room  in  which  the  two  glasses  are 
kept  is  low  the  seeds  will  rot.  The  tum- 

fig.  37. — Arrangement  for  showing  bier  which  contains  an  excessn  e  amount 
the  effect  of  the  exclusion  of  air  on  0f  moisture  prevents  the  access  of  air  that 
plant  growth.  necessary  to  the  germination  of  the  seed, 

while  the  one  which  is  kept  only  moderately  moist  allows  a  sufficient 
amount  of  air  to  come  in  contact  with  the  seeds  to  insure  germi¬ 
nation. 

(B)  The  necessity  of  air  for  the  development  of  roots  can  be  dem¬ 
onstrated  by  using  two  bottles  similar  to  those  shown  in  figure  37. 
After  filling  them  two-thirds  full  of  water  which  has  been  boiled  to 
drive  out  the  air,  place  a  cutting  of  coleus,  geranium,  or  willow  in  tin' 
receptacles,  as  indicated,  but  over  the  surface  of  the  water  in  one 

408 


38 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


bottle  pour  a  thin  layer  of  oil — castor  oil  or  sweet  oil — and  observe 
the  behavior  of  the  cuttings. 

Exercise  28. — Soil  Collection. 

Have  each  pupil  in  the  class  bring  samples  of  all  the  leading  types 
of  soils  to  be  found  on  his  home  farm  or,  if  not  living  on  a  farm,  in  the 
near  vicinity  of  his  home.  Quart  samples  will  be  large  enough. 
Empty  each  sample  out  on  a  separate  sheet  of  heavy  tough  paper. 
Compare  the  different  samples.  Bring  those  which  seem  to  be  very 
much  alike  together,  so  as  to  reduce  the  number  of  samples.  Provide 
enough  boxes  to  hold  the  different  kinds  of  soil,  and  in  these  store  the 
soils  for  future  use.  In  nearly  every  locality  the  pupils  will  be  able 
to  secure  samples  of  sand,  clay,  loam,  and  peat  or  muck,  and  an  effort 
should  be  made  to  have  these  four  types  represented  in  the  school 
collection. 

Exercise  29. — Classification  of  Soils. 

The  teacher  will  select  a  sample  of  dry  soil  from  each  of  his  most 
typical  soils  (sand,  clay,  loam,  and  peat)  and  put  them  side  by  side 
in  pans  or  on  plates  where  the  pupils  can  examine  them.  All  lumps 
should  be  broken  up  with  a  potato  masher  or  rolling-pin  or  other  piece 
of  wood.  The  pupils  should  now  examine  the  different  soils  and  take 
notes  concerning  them. 

Examine  the  samples  as  to  color  and  fineness,  rub  the  particles 
between  the  thumb  and  forefinger.  Which  are  the  coarsest  ? 

Wet  a  handful  of  each  soil  and  mix  it  in  the  hand.  Which  crum¬ 
bles  or  falls  apart  most  easily  after  wetting  ?  Which  is  most  sticky  ? 

Take  four  tumblers  nearly  full  of  water.  Into  one  put  10  grams 
of  sand,  into  another  the  same  weight  of  clay,  into  another  loam, 
and  into  another  peat.  Stir  all  thoroughly  and  set  them  aside  to  set¬ 
tle.  Which  settles  most  quickly ?  Which  most  slowly?  Stir  them 
again  and  set  them  aside.  After  one  minute  pour  off  the  liquid. 
Allow  the  settled  portions  to  dry  thoroughly  and  then  examine  them. 
It  will  be  found  that  in  each  case  the  sediment  consists  largely  of 
rather  coarse  particles  of  sand.  Weigh  each  dried  sample  and  find 
what  percentage  of  the  original  10  grams  of  each  soil  consists  of 
sand.  Which  soil  contains  the  largest  percentage  of  sand  ? 

Put  10  grams  of  peat  in  a  large  iron  spoon  or  in  a  test  tube  and 
heat  it  red-hot.  What  happens  ?  Test  the  other  soils  in  the  same 
way.  The  part  that  burns  is  humus  or  decayed  vegetable  matter. 
Which  soil  contains  the  largest  percentage  of  humus  ? 

From  the  data  at  hand  have  the  pupils  write  a  description  of 
each  class  of  soil. 


408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION, 


39 


Exercise  30. — Light  and  Heavy  Soils. 

Clay  is  called  a  heavy  soil  and  sand  a  light  soil.  Does  this  refer  to 
the  weight  of  the  soils  ? 

Weigh  a  quart  of  dry,  finely  pulverized  packed  clay  and  a  quart  of 
dry  packed  sand.  Which  is  heavier  ?  Light  and  heavy  as  applied  to 
soils  are  terms  which  refer  to  the  ease  or  difficulty  with  which  they 
can  be  plowed  or  cultivated. 

Exercise  31. — Porosity — The  Capacity  of  Soils  to  Take  in  Rainfall. 

Break  the  bottoms  off  5  long-necked  bottles,®  tie  a  small  piece  of 
cheese  cloth  or  thin  muslin  over  the  mouth  of  each  and  arrange  them 
in  a  rack  with  a  glass  tumbler  under  each,  as  shown  in  figure  38. 


Fig.  38. — Apparatus  to  test  the  capacity  of  soils  to  take  in  rainfall. 


Fill  the  bottles  to  about  the  same  height  with  different  kinds  of  soil — 
gravel  in  one,  sand  in  another,  etc. — and  firm  the  soils  by  lifting  the 
rack  and  jarring  it  down  moderately  three  or  four  times.  Now, 
with  watch  or  clock  in  hand,  and  with  a  glass  of  water  held  as  near  as 
possible  to  the  soil,  pour  water  into  one  of  the  bottles  just  rapidly 
enough  to  keep  the  surface  of  the  soil  covered  and  note  how  long 
before  it  begins  dropping  into  the  tumbler  below.  Make  a  record  of 
the  time.  Do  likewise  with  each  of  the  other  bottles  and  compare 
results.  Which  soil  takes  in  water  most  rapidly  ?  Which  is  the  most 
porous  %  What  happens  to  the  less  porous  soils  when  a  heavy  shower 
of  rain  comes  ?  How  can  a  soil  be  made  more  porous  ?  Repeat  the 

a  To  break  the  bottom  off  a  bottle  file  a  groove  in  the  bottle  parallel  with  the  bottom. 
Heat  a  poker  red-hot  and  lay  it  in  the  groove.  As  soon  as  a  small  crack  starts  from  the 
groove  draw  the  poker  around  the  bottle  and  the  crack  will  follow. 

408 


40 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


experiment  with  one  of  the  soils,  packing  the  soil  tightly  in  one  bottle 
and  leaving  it  loose  in  the  other.  What  is  the  effect  of  packing? 
Does  this  have  any  bearing  on  farm  practice  ? 

Which  soil  has  the  greatest  capacity  to  hold  water?  This  can 
be  determined  from  the  above  experiment  by  emptying  and  replacing 
each  tumbler  as  soon  as  all  free  water  has  disappeared  from  the  upper 
surface  of  the  soil  above  it.  After  water  has  ceased  dripping  from 
all  the  bottles  measure  and  compare  the  water  in  each  tumbler. 
Which  soil  continued  dripping  longest?  Which  would  drain  most 
readily  ? 

Which  soil  would  store  up  the  greatest  amount  of  moisture  ?  This 
can  be  determined  from  the  same  experiment  by  weighing  each  bottle 
before  and  after  filling  it  with  dry  soil,  and  again  after  water  has 
entirely  ceased  dripping  from  it.  The  difference  between  the  weight 
of  the  dry  soil  and  that  of  the  wet  soil  is  the  weight  of  water  stored. 
During  the  time  that  the  bottles  are  dripping,  which  may  take  several 
days,  they  should  be  covered  to  prevent  evaporation  of  water  from 
the  surface  of  the  soils. 

Make  other  practical  applications  of  the  principles  brought  out  in 
this  exercise. 

Exercise  32. — Air  in  Soils. 

In  Exercise  27  it  was  shown  that  air  is  necessary  in  soils  for  the 
proper  development  of  plants.  To  determine  the  percentage  of  air 
space  in  different  soils,  put  a  pint  of  loose  soil  into  each  of  three 
cans — sand  in  one,  clay  in  another,  and  loam  in  another.  Now  pour 
water  very  slowly  from  a  graduate  into  each  can  until  water  just 
shows  at  the  top  of  the  soil.  Pour  the  water  in  at  one  place,  leaving 
the  rest  of  the  surface  dry  so  that  the  air  can  escape  from  the  soil. 
When  the  soil  is  full  of  water  the  space  formerly  occupied  with  air 
is  filled  with  water.  How  much  water  did  it  take  to  fill  this  space  ? 
Your  graduate  will  tell  you.  Compute  the  percentage  of  air  space 
in  each  soil. 

Plan  an  experiment  to  determine  the  percentage  of  air  space  more 
accurately  by  weighing  the  soil  and  the  water  used. 

E  xercise  33. — Capillarity — The  Power  of  Soils  to  Take  up  Moisture  from 

Below. 

Arrange  4  or  5  student-lamp  chimneys,  as  shown  in  figure  39,  and 
tie  cheese  cloth  or  thin  muslin  over  their  lower  ends.  Fill  each  with 
a  different  kind  of  dry  soil,  as  in  Exercise  31.  Pour  water  into  the 
pan  beneath  until  it  stands  about  half  an  inch  above  the  lower  end 
of  the  chimneys,  then  observe  the  rise  of  water  in  the  different  soils. 
Make  notes  on  the  height  to  which  the  water  rises  and  on  the  time 
it  takes.  In  which  soil  does  the  water  rise  most  rapidly;  in  which 

408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


41 


to  the  greatest  height  ?  Which  soil  draws  up  the  greatest  amount  of 
water?  How  can  this  be  determined?  Which  soil  would  dry  out 
soonest  ?  W  hich  would  be  able  to  bring  moisture  from  the  greatest 
depth?  This  power  of  soils  to  raise  water  from  below  is  called 
capillarity.  It  is  an  important  function,  for  by  it  plants  are  able  to 
get  moisture  and  plant  food  from  the  subsoil  in  times  of  drought. 

If  chimneys  are  not  to  be  had,  this  experiment  can  be  performed 
with  the  apparatus  shown  in  figure  38  by  substituting  the  pan  for 
the  tumblers,  or  the  experiments  performed  with  the  bottles  can  be 
performed  with  the  chimneys  and  tumblers. 

If  more  accurate  tests  of  capillarity  are  desired,  it  will  be  necessary 
to  procure  a  series  of  glass  tubes  at  least  3  feet  high,  for  in  some  soils 
water  will  rise  to  that  height,  or  even  higher. 


Exercise  34. — Puddling. 


Some  soils  if  cultivated 
immediately  after  a  heavy 
rain  will  puddle,  i.  e.,  pack 
so  closely  that  when  they 
dry  out  they  bake  into  a 
hard,  almost  impenetrable, 
condition. 

Fill  four  tomato  cans  half 
full — one  with  sand,  an¬ 
other  with  clay,  another 

wifdi  loom  nnrl  onnttpr  FlQ*  39l— Apparatus  to  test  the  power  of  soils  to  take  up 
vim  loam,  ana  anotner  moisture  from  below. 

with  peat.  Add  water,  and 

stir  until  the  soils  are  about  the  consistency  of  paste.  Set  them  aside 
ten  or  fifteen  minutes.  Pour  off  the  free  water  and  stir  again.  Set 
them  in  the  sunlight  and  allow  them  to  dry  thoroughly,  or,  better, 
set  them  over  a  slow  fire  for  several  hours.  Which  soils  baked  ? 
Which  could  be  most  easily  stirred  or  cultivated  after  drying  ?  In 
farm  practice  which  could  be  worked  soonest  after  a  rain  without 
danger  of  puddling  ?  Which  could  be  worked  earliest  in  the  spring  ? 


Exercise  35. — The  Effect  of  Lime  on  Clay  Soils.a 

(A)  Take  a  vessel  holding  a  pint  or  more  and  fill  it  with  clear  well 
water.  Put  into  it  a  couple  of  spoonfuls  of  fine  clay  soil  and  stir  up 
thoroughly  for  three  or  four  minutes.  Let  it  settle  for  five  minutes. 
Then  take  two  clear  glass  bottles,  holding  about  a  half  pint  each, 
and  fill  them  with  water  from  the  vessel,  being  careful  not  to  stir  up 
the  sediment  again.  Into  one  of  the  bottles  put  a  piece  of  lime  about 

a  After  Fisher.  Practical  Studies  in  Agriculture  for  Public  Schools.  Purdue 
University. 

40S 


42 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


as  large  as  a  bean  and  shake  the  contents  well.  Put  nothing  in  the 
other  bottle.  Set  the  two  bottles  aside  and  notice  any  difference  or 
changes  that  take  place  in  an  hour  or  two  and  over  night. 

(B)  Take  two  deep  dishes  or  other  vessels  and  fill  them  with  fine 
clay  soil.  Into  one  put  a  couple  of  teaspoonfuls  of  lime,  according  to 
the  size  of  the  dish.  Put  no  lime  in  the  other  dish.  Stir  up  both  lots 
of  soil  with  water  until  they  are  thoroughly  sloppy.  Set  them  where 
they  will  dry  out.  When  they  are  completely  dry  remove  the  cakes 
of  soil  from  the  dishes  and  pulverize.  What  differences  do  you 
notice?  Can  you  explain  these  differences?  Do  the  results  in  the 
bottles  help  you  to  understand  the  action  of  the  lime  in  the  soil? 
Could  you  expect  a  similar  result  from  putting  lime  on  stiff  clay  soil  ? 
Do  you  think  it  would  be  a  good  idea  to  try  it  ? 

Exercise  36. — Action  of  Frost  on  Soils. 

Puddle  a  pint  of  stiff  clay,  mold  it  into  a  ball,  and  bake  it  on  the 
stove.  In  freezing  weather  moisten  this  ball  and  put  it  out  of  doors 
over  night.  If  it  does  not  break  up  the  first  night,  moisten  it  again 
and  subject  it  to  the  action  of  frost.  What  happens?  From  this 
result  what  would  you  say  of  the  practice  of  fall  plowing  heavy 
clay  land?  Is  there  any  advantage  in  fall  plowing  aside  from  the 
action  of  frost  on  the  soil  ? 

Exercise  37. — Temperature  of  Soils  as  Affected  by  Color. 

Sink  a  box  about  2  feet  long  by  1  foot  wide  and  8  or  10  inches  deep 
into  the  soil  so  that  the  top  is  even  with  the  surface  of  the  ground. 
Fill  the  box  with  the  lightest-colored  sand  you  can  find.  Cover  half 
of  it  with  a  thin  layer  of  lampblack — just  enough  to  blacken  the 
whole  surface.  Insert  the  bulb  of  one  thermometer  about  one-half 
inch  under  the  surface  of  the  uncolored  sand  and  another  one-half 
inch  under  the  surface  of  the  colored  sand,  and  on  a  sunny  day  take 
readings  of  the  thermometers,  every  hour  from  daylight  until  two  or 
three  hours  after  sunset. 

Perform  a  similar  experiment  with  peat  or  the  darkest-colored  soil 
you  can  find,  except  that  half  of  this  soil  is  colored  white  with  lime 
dust.  Take  readings  as  before.  Compare  results.  What  conclusions 
may  be  drawn  as  to  the  influence  of  color  on  the  temperature  of  soils? 
Are  the  differences  recorded  in  sunlight  as  marked  as  when  the  sun  is 
not  shining?  Other  conditions  being  equal,  which  soil  would  soonest 
be  warm  enough  for  planting  in  the  spring  ? 

The  influence  of  color  upon  temperature  may  be  illustrated  in  a 
simple  way  b}r  scattering  lampblack  or  dark-colored  earth  on  snow 
when  the  sun  is  shining. 

408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION.  43 

Exercise  38. — Temperature  as  Affected  by  Moisture. 

Take  two  tomato  cans  and  in  the  bottom  of  one  punch  a  number  of 
holes  for  drainage.  Fill  both  with  the  same  kind  of  soil.  Wet  the 
soils  thoroughly.  Insert  the  bulb  of  a  thermometer  an  inch  under 
the  surface  of  each  and  set  them  in  direct  sunlight.  Take  readings 
from  each  thermometer  every  two  hours  for  two  or  three  days,  and 
record  the  temperatures.  Compare  the  readings  and  see  what  results 
follow  as  the  moisture  disappears  from  the  can  provided  with  drainage. 

What  is  the  conclusion  as  to  the  temperature  of  drained  and  un¬ 
drained  soils?  Which  would  be  the  earlier  soil  in  spring?  Which 
the  later  as  the  fall  rains  start  in?  Would  there  be  a  tendency  to 
shorten  or  to  lengthen  the  growing  season  by  draining  wet  soils? 

Exercise  39. — Temperature  of  Soils  as  Affected  by  Inclination  of  the  Surface  > 

or  Exposure  to  the  Sun. 

Fill  three  boxes,  about  a  foot  square  and  6  or  8  inches  deep,  with 
the  same  kind  of  soil  and  set  them  in  the  sunlight  side  by  side  with 
the  same  exposure,  except  that  one  is  level,  one  tilted  about  30°  to  the 
south,  and  the  other  tilted  about  30°  to  the  north.  Insert  the  bulb  of 
a  thermometer  about  one-half  inch  under  the  surface  of  the  soil  in 
each  box,  take  readings  every  hour  during  a  sunny  day,  and  compare 
results.  In  which  box  were  the  highest  temperatures  recorded  ?  Ask 
pupils  to  explain  this.  What  practical  bearing  has  this  upon  the 
selection  of  farms?  With  other  conditions  alike,  which  would  be 
ready  to  work  earlier  in  the  spring,  a  north  slope  or  a  south  slope  ? 

Exercise  40. — Free  Moisture  in  Soils. 

Take  four  slender  baking-powder  cans  of  the  same  size,  with  tops 
and  bottoms  removed,  and  tie  over  one  end  of  each  a  piece  of  cheese 
cloth  or  thin  muslin. 

Fill  one  can  to  within  an  inch  of  the  top  with  coarse  dry  sand, 
another  with  dry  loam,  the  third  with  dry  pulverized  clay,  and  the 
fourth  with  dry  muck  or  leaf  mold  mixed  with  sand.  Weigh  the 
soils  before  putting  them  into  the  cans,  in  order  to  have  a  record  of 
the  weights  for  use  in  the  next  experiment.  If  any  of  the  soils  con¬ 
tain  pebbles  or  clods,  these  should  be  removed  by  sifting.  Set  the 
cans  where  they  can  drain  readily  into  separate  vessels;  then  have 
four  pupils  pour  water  slowly  into  each  can  until  it  begins  to  drip 
from  the  bottom,  using  care  not  to  have  any  water  stand  on  the  sur¬ 
face  of  the  soils  when  the  dripping  begins.  Allow 'the  cans  to  stand 
until  all  drip  has  ceased.  Measure  or  weigh  the  drainage  from  each 
can.  This  is  free  water — the  water  which  would  be  removed  from 
soils  by  thorough  underdrainage. 

408 


44 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


From  which  soil  was  the  greatest  amount  of  drainage  collected  ? 
Does  the  amount  of  drainage  water  appear  to  have  any  relation  to  the 
fineness  of  the  soil  ?  Which  soil  drained  the  most  rapidly  ?  Do  soils 
underlain  with  sand  (having  a  sandy  subsoil)  need  underdraining  as 
a  rule  ? 

Exercise  41. — Capillary  Moisture  in  Soils. 

As  soon  as  all  drip  from  the  soils  used  in  Exercise  40  has  ceased 
weigh  each  can,  and  by  comparing  this  weight  with  the  dry  weight 
of  the  same  soil  determine  how  much  moisture  has  been  held  by  each 
soil.  The  difference  in  each  case  represents  approximately  the  capil¬ 
lary  moisture  in  the  soil — that  is,  the  moisture  which  is  held  in  sus¬ 
pension  between  the  soil  particles. 

Which  soil  retained  the  greatest  amount  of  capillary  moisture? 
This  was  what  per  cent  of  the  dry  weight  ?  Does  the  amount  bear 
any  relation  to  the  fineness  of  the  soils?  To  the  amount  of  organic 
matter?  Find  the  volume  of  your  cans  and  estimate  how  many 
pounds  of  water  per  cubic  foot  each  soil  is  capable  of  holding.  What 
does  it  represent  in  inches  of  rainfall  ? 

Capillary  moisture  and  film  moisture  (see  Exercise  42)  are  sup¬ 
posed  to  dissolve  from  the  surface  of  soil  particles  plant  food  which 
is  taken  up  by  the  roots  of  plants.  Does  a  fine  or  a  coarse  soil  present 
a  greater  amount  of  surface  to  the  action  of  water?  Does  the  fine¬ 
ness  of  a  soil  then  bear  any  relation  to  its  fertility  ?  What  ? 

The  teacher  can  illustrate  the  increase  of  surface  due  to  fineness  of 
division  by  taking  an  inch  cube  of  wood  and  dipping  it  in  ink.  Show 
the  pupils  that  it  now  presents  a  surface  of  6  square  inches;  split  it 
in  two  and  show  them  the  2  square  inches  of  uncolored  surface  which 
have  been  added  by  division.  Have  seedlings  of  radishes  growing 
in  a  box  of  sandy  soil.  Pull  some  of  these  up  and  show  how  the  root 
hairs  cling  to  the  particles  of  soil. 

Exercise  42. — Hygroscopic  Moisture  in  Soils. 

The  presence  of  hygroscopic  or  film  moisture  in  soils  may  be  dem¬ 
onstrated  by  spreading  out  and  air-drying  thoroughly  one  of  the  soil 
samples  used  in  the  preceding  exercises;  then  putting  a  small  portion 
of  it  into  a  test  tube  and  heating  it  to  a  high  temperature.  If  an}/ 
moisture  condenses  on  the  inside  of  the  tube  it  is  hygroscopic  or 
film  moisture  from  the  soil.  Or  weigh  out  10  grams  of  air-dry  soil, 
put  it  in  an  iron  spoon,  heat  it  red  hot,  and  again  weigh  it.  From 
the  weights  before  and  after  heating  determine  the  film  moisture. 

408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION.  45 

Exercise  43. — The  Influence  of  Tillage  and  Mulches  on  the  Retention  of 

Moisture  in  Soils. 

Fill  four  lamp  chimneys,  prepared  as  in  figure  39,  or  better,  four 
12-inch  lengths  of  4-inch  down-spouting  or  conductor  pipe  prepared 
in  a  similar  manner,  with  fine  garden  loam  to  within  2  inches  of  the 
top.  Immerse  these  tubes  for  a  few  seconds  in  water.  Cover  the 
surface  of  the  soil  in  one  tube  with  1J  inches  of  the  same  kind  of  soil, 
and  pack  it  down.  Cover  another  with  1  \  inches  of  the  same  kind  of 
soil,  and  keep  it  loose  by  stirring  from  time  to  time.  Cover  another 
with  1 J  inches  of  road  dust,  and  another  with  1J  inches  of  chaff  or 
finely  cut  straw.  Suspend  the  tubes  where  drainage  will  be  free  and 
where  all  will  be  subjected  to  the  same  conditions  as  to  sunlight  and 
currents  of  air.  Weigh  them  morning  and  evening  for  three  or  four 
days. 

Which  tube  lost  moisture  most  rapidly?  Which  most  slowly? 
What  is  the  conclusion  as  to  the  influence  of  cultivation  or  mulches 
upon  the  retention  of  moisture  in  the  soil?  Is  the  destruction  of 
weeds  the  only  object  sought  in  cultivating  crops? 

Exercise  44. — To  Show  the  Effect  of  Plowing  Down  Manures  and  Clods. a 

Fill  three  chimneys  or  tin  cylinders,  prepared  as  in  Exercise  43, 
three-fourths  full  of  fine  dry  soil.  On  top  of  this  soil  in  one  chimney 
pack  1  inch  of  finely  cut,  dry  straw,  on  another  1  inch  of  well-rotted 
straw  or  manure,  and  on  the  other  1  inch  of  hard  clay  broken  into 
pieces  about  the  size  of  large  peas.  Fill  the  chimneys  with  more  fine 
dry  soil  and  set  them  in  a  pan  containing  a  half  inch  or  so  of  water. 
Keep  water  in  the  pan  all  of  the  time.  Note  the  rise  of  water  in  the 
chimneys.  Does  it  pass  through  the  dry  straw  or  clods  as  quickly  as 
it  does  through  the  rotted  material?  The  straw  and  rotted  manure 
represent  material  plowed  under  and  lying  in  the  bottom  of  the 
furrow,  and  the  clods  represent  a  hard  baked  surface  plowed  under. 
The  soil  on  top  represents  the  furrow  slice.  Apply  this  experiment 
to  farm  practice.  In  which  condition  do  you  think  a  crop  would 
suffer  least  from  dry  weather?  When  should  strawy  manure  be 
plowed  under,  spring  or  autumn?  When  hard  baked  clay?  Why? 
(See  Exercise  36.) 

Exercise  45. — Influence  of  Drainage  upon  Plant  Growth. 

We  have  learned  from  Exercise  38  how  the  amount  of  moisture  in 
the  soil,  or,  in  other  words,  how  drainage  affects  the  temperature. 
The  influence  of  drainage  upon  plant  growth  can  be  shown  by  planting 
corn,  beans,  or  almost  any  seed  in  the  same  kind  of  soil  in  two  tomato 

a  Adapted  from  Fisher.  Practical  studies  in  Agriculture  for  Public  Schools. 
Purdue  University. 

408 


46 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


cans,  one  with  holes  punched  in  the  bottom  and  the  other  without. 
Apply  the  same  amount  of  water  to  each  can  from  day  to  day,  and 
observe  the  condition  of  the  plants  for  two  or  three  weeks. 

As  soon  as  any  marked  difference  in  favor  of  the  drained  soil  is 
manifested  in  the  condition  of  the  growing  plants,  seal  the  holes  in 
the  bottom  of  the  drained  can  with  paraffin  or  wax,  and  punch  holes 
in  the  bottom  of  the  other  can.  Continue  to  apply  water  as  before 
and  note  any  changes  that  occur. 

Exercise  46. — Effect  of  Manures  on  Plant  Growth. 

In  this  exercise  wheat  is  to  be  grown  for  three  weeks  on  soils  treated 
in  different  ways.  The  first  thing  to  do  is  to  put  about  150  or  200 
plump  kernels  of  wheat  in  the  seed  tester  (fig.  12)  so  that  it  will  be 
sprouted  by  the  time  the  soil  is  ready  for  planting. 

Now  secure  enough  sandy  or  sandy  loam  soil  to  fill  8  common  tum¬ 
blers  or  drinking  glasses.  Pulverize  the  soil,  mix  it  thoroughly  and 
divide  it  into  4  equal  parts,  putting  each  fourth  into  a  granite  or 
earthenware  pan,  and  numbering  the  pans  1,  2,  3,  and  4. 

The  soil  in  pan  No.  1  should  be  used  as  a  check,  that  is,  it  should 
not  be  treated  with  any  fertilizer  or  manure.  It  will  thus  serve  as  a 
means  of  comparison  to  show  the  effect  of  applying  manures  to  the 
other  soils. 

The  soil  in  pan  No.  2  should  be  treated  with  nitrogen  as  follows: 
Secure  from  a  druggist  or  a  fertilizer  dealer  a  small  quantity  of 
nitrate  of  soda  and  dissolve  one  level  teaspoonful  of  this  material  in 
2  quarts  of  clean  rain  water.  Take  1  ounce  of  this  solution  (meas¬ 
ured  in  a  graduate  or  an  ounce  bottle)  and  sprinkle  it  carefully  over 
the  whole  surface  of  the  soil  in  pan  No.  2.  Sprinkle  enough  more 
clean  rain  water  over  the  soil  to  wash  the  nitrate  of  soda  into  the  soil. 

To  the  soil  in  pan  No.  3  add  as  much  dry  finely  pulverized  barnyard 
manure  as  can  be  put  (without  packing)  in  a  10-gauge  shotgun  shell. 
With  a  case  knife  or  clean  glass  rod  mix  the  manure  thoroughly  with 
the  soil.  Sprinkle  the  soil  with  clean  rain  water  as  in  pan  No.  2. 

Green  manure  is  to  be  added  to  the  soil  in  pan  No.  4.  To  prepare 
this  dig  up  a  number  of  plants  of  clover,  alfalfa,  or  cowpeas,  and 
carefully  wash  all  dirt  from  the  roots.  Select  two  or  three  plants 
having  nodules  (small  irregular  knots  formed  by  nitrogen-gathering 
bacteria)  on  the  roots  and  run  them  (root  and  top)  through  a  meat 
chopper  or  sausage  grinder,  or  chop  them  with  a  chopping  knife  until 
they  become  a  shredded  pulpy  mass.  Do  not  lose  the  green  watery 
juice  that  is  squeezed  from  the  plants  in  grinding  or  chopping,  but 
mix  it  in  with  the  pulp.  To  the  soil  in  pan  No.  4  add  a  10-gauge 
shotgun  shell  twice  full  of  this  pulp,  mix  thoroughly,  and  wash  down 
as  directed  for  pan  No.  3. 

408 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION.  47 

Place  the  four  pans  in  the  sunshine  and  leave  them  for  about 
twenty-four  hours. 

On  the  following  day  bring  the  soil  in  the  different  pans  to  the 
proper  condition  of  moisture — just  wet  enough  to  hold  together  after 
squeezing  in  the  hand,  but  not  so  wet  that  water  can  easily  be  squeezed 
from  it.  Fill  two  tumblers  to  within  one-lialf  inch  of  the  top  from 
each  pan.  The  tumblers  filled  from  pan  No.  1  should  be  labeled 
“No.  1,  check,”  those  from  pan  No.  2,  “No.  2,  nitrogen,”  those  from 
pan  No.  3,  “No.  3,  barnyard  manure,”  and  those  from  pan  No.  4, 
“No.  4,  green  manure.” 

From  the  seed  tester  select  five  strong,  well-sprouted  grains  of 
wheat  for  each  tumbler.  Make  a  straight  groove  one-quarter  inch 
deep  in  the  soil  of  each  tumbler  and  place  in  it  at  regular  intervals 
the  five  selected  grains  of  wheat,  using  care  to  set  the  kernels  with  the 
sprouts  right  side  up  and  all  facing  oneway,  so  that  the  plants  will  all 
come  up  regularly  at  about  the  same  time.  Cover  the  grains  and 
set  the  tumblers  in  a  light,  warm  place. 

Allow  the  plants  to  grow  three  weeks.  Water  them  each  day,  but 
do  not  use  enough  water  to  soak  the  soil.  The  tumblers  have  no 
drainage  and  if  water  stands  in  the  bottom  of  the  tumblers  it  will 
shut  out  the  oxygen  needed  by  the  roots  of  the  plants. 

At  the  end  of  the  three  weeks  compare  the  plants  in  the  four  sets  of 
tumblers  as  to  color,  vigor,  height  of  plant,  and  root  development. 

Judging  by  the  condition  of  the  plants,  was  the  soil  improved  by 
the  application  of  a  manure  ?  Which  treatment  gave  the  best  result  ? 
Which  soil  seems  to  be  in  the  best  physical  condition — i.  e.,  loose  and 
friable  ?  Which  contains  the  most  humus  ?  How  was  this  humus 
provided  ?  If  you  had  a  farm  of  this  kind  of  soil  which  manure 
would  you  use? 

HELPS  FOR  TEACHERS. 

• 

Teachers  will  find  additional  suggestions  for  school  exercises  and 
problems  in  agriculture  in  nearly  every  elementary  text-book  on  the 
subject.  In  addition  to  these,  the  following  books  and  pamphlets 
are  devoted  entirely  to  such  exercises  and  problems : 

Rural  School  Agriculture,  by  W.  M.  Hays  and  others,  St.  Paul, 
Minn. 

Rural  School  Agriculture,  by  C.  W.  Davis,  New  York,  1907. 

One  Hundred  Experiments  in  Elementary  Agriculture  for  California 
Schools,  by  R.  O.  Johnson,  San  Francisco,  1908. 

One  Hundred  Lessons  in  Agriculture,  by  A.  W:  Nolan,  Morgan¬ 
town,  W.  Va.,  1909. 

Farm  Arithmetic,  by  Miss  Jessie  Field,  Shenandoah,  Iowa,  1909. 

408 


48 


SCHOOL  EXERCISES  IN  PLANT  PRODUCTION. 


Outlines  of  Agriculture  for  Rural  Schools,  by  C.  M.  Evans,  Chicago, 
1910. 

Teachers  will  do  well  to  purchase  through  their  local  dealers  copies 
of  as  many  as  possible  of  these  books  to  be  used  for  reference  purposes. 
Almost  any  local  stationer  or  book  dealer  will  be  able  to  procure  them. 
In  addition  to  these  there  are  many  free  publications  that  will  be 
helpful  to  both  teachers  and  pupils. 

The  free  publications  of  the  United  States  Department  of  Agricul¬ 
ture  can  be  selected  from  lists  which  can  be  procured  from  Members 
of  Congress  or  from  the  Secretary  of  Agriculture.  One  of  these  lists 
has  been  prepared  especially  for  teachers  and  is  entitled  “  Free  Publi¬ 
cations  of  the  Department  of  Agriculture  Classified  for  the  Use  of 
Teachers.”  (O.  E.  S.  Cir.  94.) 

The  publications  of  the  several  state  institutions  are  in  most  cases 
free  to  teachers  residing  in  the  State,  but  are  not  available  for  others. 
Every  state  experiment  station  issues  free  agricultural  bulletins, 
and  in  addition  to  these  the  following  state  institutions  have  issued 
pamphlets  containing  lessons  or  exercises  for  public  schools: 

Alabama — Tuskegee  Institute;  Connecticut — State  Board  of  Edu¬ 
cation,  Hartford;  Geogria — Education  Department  (Ann.  Rpt.  1904), 
Atlanta;  Indiana — Purdue  University  bulletins,  Lafayette;  Kansas — 
State  Agricultural  College  (Industrialist),  Manhattan;  Massachu¬ 
setts — Agricultural  College,  Department  of  Agricultural  Education, 
Amherst;  Michigan — Agricultural  College,  East  Lansing,  and  State 
Department  of  Public  Instruction,  Lansing;  Minnesota — College  of 
Agriculture,  University  Farm,  St.  Paul;  Missouri — University  of  Mis¬ 
souri  bulletins,  and  State  Board  of  Agriculture  bulletins,  Columbia; 
Nebraska— College  of  Agriculture,  and  State  Department  of  Educa¬ 
tion,  Lincoln;  New  Hampshire — College  of  Agriculture  and  Mechanic 
Arts,  Durham;  New  York — State  College  of  Agriculture  (Rural  School 
Leaflets),  Ithaca,  and  State  Education  Department,  Albany;  Ohio — 
College  of  Agriculture  (Extension  Bulletins),  Columbus;  Oklahoma — 
Agricultural  and  Mechanical  College,  Stillwater;  Rhode  Island — 
State  College  (Nature  Guard),  Kingston;  South  Dakota — State  Col¬ 
lege  of  Agriculture  and  Mechanic  Arts,  Brookings. 


[A  list  giving  the  titles  of  all  Farmers’  Bulletins  available  for  distribution  will  be 
sent  free  upon  application  to  a  Member  of  Congress  or  the  Secretary  of  Agriculture.] 

408 


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